轮机英语8套(6)

1、T eam members share accurate understanding of current and predicted engine-room and associated systems state, and of .

A. external environment

B.external resources

C.internal environment

D.internal resources

2、Which of the equipment listed is most effective in processing bilge slops for overboard discharge? (172917:第2 章船舶辅助机械:748) 查看备注查看答案A. A 100PPM oily water separator. B. the second engineer

C. the third engineer

D. the fourth engineer

6、Under ISPS Code, the ship to which it applies has to carry _. (174865:第5 章国际公约、规则:235) 查看备注查看答案

A. an International Ship Security Certificate

B. an International O i l Pollution Prevention Certificate

C. a Safety Management Certificate

D. an International Ballast Water Management Certificate

7、In order to protect the aerobic bacteria from death, the sewage plant should work

B. Assembling the lube oil purifier as a separator and aligning it to the bilge overboard. .

C. A 15PPM oily water separator

D. A magnetic duplex strainer

3、During the PSC inspection, under the provisions of SOLAS74, which one may not be regarded as clear grounds for ships detainment? (174599:第4 章船舶轮机管理业务:621) 查看备注查看答案

A. Excess amount of oily-water mixtures in bilges

B. Insulation of piping including exhaust pipes in engine room contaminated by oil

C. Improper operation of bilge pumping arrangements

D. Paint peeling off the uptake

4、A gearbox is used in a ship driven by a medium-speed diesel engine

A.to govern the engine speed

B.to increase the engine speed

C.to reduce the engine speed

D.to fix the propeller shaft

5、Usually _ handles the majority of the correspondence and negotiation needed during transactions of stores and spare parts in the engine department. (174448:第4 章船舶轮机管理业务:470) 查看备注查看答案

A. the chief engineer A.at 3-month intervals

B.at 14-day intervals

C.at 7-day intervals

D.continuously

8、After charging solid waste, close the dump chute, and ignite it with the _.

A.auxiliary and waste oil burners

B.auxiliary burner or the waste oil burner

C.auxiliary burner

D.waste oil burner

9、The separating effect of oil separator is not very good, the reason may be _ 。(173091:第2 章船舶辅助机械:922) 查看备注查看答案

A. too little seal water

B. improper gravity disc

C. oil discharging pump not working very well

D. low water level of the working water

10、Proper internal lubrication of a hydraulic anchor windlass left idle for extended periods can be accomplished by _. (173335:第2 章船舶辅助机械:1166) 查看备注查看答案

A. performing a check run on the unit at regular intervals

B. testing the hydraulic fluid for proper pH

C. checking the reservoir for proper level

D.

cleaning strainers at regular intervals

11、Check valve isn’t used to control _.

A.direction of oil flow

B.bypass of filter

C.back pressure of return oil

D.high pressure overflow

12、The emergency generator or emergency battery is connected to( )on most large ship. (173617:第3 章船舶电气和自动化:150) 查看备注查看答案

A. distribution boards

B. section boards

C. emergency switch boards

D. main switch boards

13、In a series circuit, which value will remain unchanged at all places in the circuit? (173721:第3 章船舶电气和自动化:254) 查看备注查看答案

A. Voltage.

B. Current.

C. Resistance.

D. Inductance.

14、Which of the following is not one of the preconditions for the oil or oily mixtures from machinery spaces to be discharged into the sea?

A.the oily mixture does not originate from cargo pumproom bilges on oil tankers.

B.the instantatneous discharging rate is no more than 30 liter per nautical mile.

C.the oily mixture is processed through an approved equipment

D.the ship is proceeding en route.

15、What is the application of high-speed diesel engines at sea? (170845:第1 章船舶主推进装置:79) 查看备注查看答案

1. They are used for emergency power generation to small applications

2. They are used for electrical power generation on board ships driven by medium-speed propulsion engines.

3. They can be used on tugs, ferries and barges etc. as main engines.

4. All of the above.

A.2+3

B.3

C.1+2

D.1+2+3

16、You are attempting to parallel two AC generators and the synchroscope pointer is revolving in the slow direction. This indicates that the frequency of the incoming machine is _ _. (173577:第3 章船舶电气和自动化:110) 查看备注查看答案

A. higher than the bus frequency

B. lower than the bus frequency

C. the same as the bus frequency but out of phase with it

D. the same as the bus frequency, and the circuit breaker may be closed at any pointer position

17、The drawing is about __

A.cylinder oil system

B.jacket water system

C.fuel oil system

D.lube oil system

18、for crash maneuvers the lever is moved from one extreme to the other, the sequence is _ _.

A.braking, starting and reaching critical speed

B.braking, reaching full speed(ahead or astern) and stopping

C.stopping oil supply, braking and reaching full speed(ahead or astern)

D.braking, starting and reaching full speed(ahead or astern)

19、A centrifugal pump may fail to deliver water when first started if the __. (172685:第2 章船舶辅助机械:516) 查看备注查看答案

A. water seal pipe is plugged

B. pump is not primed

C. seal ring is improperly located

D. impeller is flooded

20、A transformer in an electric circuit serves to . (173701:第3 章船舶电气和自动化:234) 查看备注查看答案

A. generate its own electrical power

B. transform electrical energy into mechanical energy

C. increase or decrease circuit voltage as required

D. convert AC current to DC current

21、UMS are mainly unattended overnight and during this time _ should have control of the main engine. (173967:第3 章船舶电气和自动化(04 规则不考):500) 查看备注查看答案

A. the chief engineer

B. the engineer on cabin watch

C. the bridge officer on watch

D. the master

22、what is the purpose of sub-cooling R22 in the condenser?

A.to remove latent heat of vaporization and the suction piping transfer

B.to reduce the load on the compressor

C.to stop the liquid from flashing

D.to increase the system efficiency by sensible heat transfer

23、In which of the areas listed is a fire resulting from spontaneous combustion most likely to occur? (174136:第4 章船舶轮机管理业务:158) 查看备注查看答案

A. Engine room bilges.

B. Paint locker.

C. Battery storage locker.

D. Fuel oil tank.

24、An advantage of DC motors over AC motors is that they . (173689:第3 章船舶电气和自动化:222) 查看备注查看答案

A. are less expensive

B. require Iess maintenance

C. can be started across the line

D. offer a more effective means of controlling speed

25、The “_” of each bearing should be measured, with the shell and cap assembled as for running the nuts should be tightened the full amount and a check made that the clearance between cap and housing is zero.

A.thickness

B.nip

C.clearance

D.distance

26、The treatment of the fuel oils involves storage, heating, filtering and __. (173001:第2 章船舶辅助机械:832) 查看备注查看答案

A. centrifuging

B. pressurizing

C. atomization

D. igniting

27、camshafts are usually driven by timing gears or

A.push rods

B.rocker arms

C.flywheels

D.chain drives

28、After received the “finished with engine”instruction, which of the following operations is false?

A.stop the jacket water pump immediately and shut off the correspondence valves

B.shut off the main starting valve

C.stop the fuel oil booster pump

D.stop the sea water pump immediately and shut off the correspondence valves

29、a casing drain is provided for axial piston and bent axis variable stroke pumps to

.

A.drain off any accumulated water from the pump casing prior to its being started.

B.vent off any accumulated air from the system

C.prevent damage due to agitation and overheating of oil accumulated in the casing as a result of minor internal leakage.

D.assist the complete removal of hydraulic oil from the system prior to opening for major or minor repairs.

30、If a DC motor runs hot, the cause may be _ __. (173714:第3 章船舶电气和自动化:247) 查看备注查看答案

A. high mica condition

B. low ambient temperature

C. clogged ventilation ducts

D. an open in the shunt field

31、The main purpose of inspection for a running diesel engine is . (174030:第4 章船舶轮机管理业务:52) 查看备注查看答案

A. testing for the mechanical load and the thermal load

B. inspecting thermal and mechanical condition of the engine

C. inspecting each system and exhaust temperature

D. testing for compress pressure and explosion pressure

32、The time of discharging oil is short, but oily water separator discharges oil frequently. The possible reason is ( ). (172949:第2 章船舶辅助机械:780) 查看备注查看答案

A. the sensor of low oil level is fully covered by sludge

B. the coarse strainer before the pump in suction system is clogged

C. the screw pump is worn seriously and volumetric efficiency is decreased.

D. bilge suction valve is clogged

33、what will be the possible result of adding extra electrical appliances to a circuit?

A.The insulation will be improved

B.The wires will become insulated.

C.The circuit is likely to be changed

D.the fire is likely to occur

34、In a general cargo crane, is fitted to lift the cargo load. (173294:第2 章船舶辅助机械:1125) 查看备注查看答案

A. the slowing motor

B. the hoisting motor

C. the luffing motor

D.

none of the above

35、If the capacity of a centrifugal pump decreases gradually over a long period of time, you should replace the ( ) . (172624:第2 章船舶辅助机械:455) 查看备注查看答案

A. packing gland

B. mechanical seals

C. lantern rings

D. wearing rings

36、when determining the needs of the intended voyage, the chief engineer will consulted with _, taking into consideration the requirement for fuel, water, lubricants, chemicals and any other requirements.

A.chief officer

B.second engineer officer

C.master

D.chief engineer officer

37、it can be seen therefore that in a closed loop control system the control action is dependent on the _ .

A.output

B.error

C.input

D.desired value

38、In the voyage, when carring out abandon ship drill, should be tested every time.

A.the emergency lighting system for muster and abandon ship.

B.main/auxiliary steering gear changing

C.air/oil emergency shut-down

D.M.

E. emergency operation

39、Generator brushes are staggered to . (173505:第3 章船舶电气和自动化:38) 查看备注查看答案

A. reduce current pulsations

B. reduce brush chatter

C. prevent uneven commutator wear

D. allow greater power generation

40、It is important to note that when an excessive amount of water is present in the fuel the temperature for centrifugine must be kept below , otherwise forming and agitation of the fuel takes place.

A.the flash point of the fuel

B.the boiling point of water

C.the flammable point of the fuel

D.the condensating point of water

41、Which of following has no direct relation to ISM Code?

A.SMS

B.ORB

C.SMC

D.DOC

42、The headers of heat exchangers form a natural collecting point for all kinds of debris passing through the salt water system; due to the reduction in which occurs within them.

A.temperature

B.flow velocity

C.viscosity

D.pressure

43、Effective horsepower is the power developed by the _ in the cylinder, but some of this is lost by friction within the engine.

A.connecting rod

B.crank

C.crankshaft

D.piston

44、In the event of a small bunker oil spill on deck occurring while bunkering, you should______

A.wash down the area immediately with a fire hose

B.wash down the area with kerosene

C.cover the area with absorbent material

D.cover the area with foam

45、In an four-stroke engine the camshaft rotates at . (170928:第1 章船舶主推进装置:162) 查看备注查看答案

A. half the engine speed

B. the engine speed

C. twice the engine speed

D. four times the engine speed

46、which class of fire should burning diesel oil be treated as?

A. Class ‘C’

B.Class ‘D’

C.Class ‘B’

D.Class ‘D’

47、Before being used the fuel service tank should be drained of . (171603:第1 章船舶主推进装置:837) 查看备注查看答案

A. soda solution

B. ballast

C. mechanical impurities

D. water and residuals

48、A pyrometer is an instrument used to measure the temperature of the diesel engine

. (172095:第1 章船舶主推进装置:1329) 查看备注查看答案

A. exhaust

B. fuel oil

C. cooling water

D. cylinder liner

49、If you install a new hydraulic hose in a hydraulic system, the hose must be long enough to allow for contraction to prevent__ _ (173464:第2 章船舶辅助机械:1295) 查看备注查看答案

A. failure of the hydraulic hose

B. excessive flow through the line

C. friction in other areas of the hydraulic system

D. overheating of the hydraulic fluid

50、To shut down a diesel engine after it exceeds the set maximum speed, which type of device listed should be used? (172034:第1 章船舶主推进装置:1268) 查看备注查看答案

A. Speed limiting governor

B. Overspeed governor

C. Overspeed trip

D. Overspeed relay

51、How can the chance of contaminating hydraulic fluid be decreased when working on hydraulic systems? (173455:第2 章船舶辅助机械:1286) 查看备注查看答案

A. Clean the fittings before they are disconnected.

B. Place drip pans under leaky fittings.

C. Seal any cracks in lines with Permatex (美国产一种粘合剂和密封胶的品牌).

D. Coat all threads with graphite oil.

52、The most critical part of the bunkering operations, which can result in an oil spill, is when the _ _. (174412:第4 章船舶轮机管理业务:434) 查看备注查看答案

A. hose joints are made up

B. tanks are being topped off

C. system is being lined up

D. pumping operation is first started

53、In a pneumatic automation system, a unit producing a signal to govern the position of the controller of the measured variable, relative to the value of the measured variable, is said to have ( ). (173889:第3 章船舶电气和自动化(04 规则不考):422) 查看备注查看答案

A. reset action

B. proportional action

C. two position action

D. rate action

54、The main purpose of warming up the main engine is _

A.to reduce heat stress

B.to improve firing and starting performance

C.for fuel saving

D.to reduce low temperature corrosion

55、oil mist detectors are usually used on board to detect oil mist density within__

A.fuel tanks

B.the engine crankcase

C.drain tanks

D.the engine scavenge boxes

56、A number of cylinder liners are enclosed in one cast iron casing to form a __. (171288:第1 章船舶主推进装置:522) 查看备注查看答案

A. cylinder cover

B. cylinder frame

C. cylinder block

D. bed-plate

57、, where minor repairs are carried out with a ship in service, often during a stay in port. This may be remote from a shiprepair site. (174466:第4 章船舶轮机管理业务:488) 查看备注查看答案

A. Voyage repairs

B.

Routine docking C.

Damage repairs D.

Conversion

58、What is the ultimate purpose of requirements covering machinery and electrical installations?

A.to protect the safety of the ship, passengers and crew

B.to protect equipment under emergencies

C.to ensure the right operation of machines

D.to maintain the services

59、In order to reduce the chance of detentions ships should routinely verify the following except for __.

A. all O i l Record Book entries completed according to Marpol

B.operation of the oily water separator monitor able to demonstrated.

C.cleaning all associated monitor, alarm and stopping device.

D.operation of the oily water separator able to demonstrated.

60、In maritime labour convention, hours of rest may be divided into no more than periods, one of which shall be at least six hour in length, and the interval between consecutive periods of rest shall not exceed hours.

A.14

B.10

C.12

D.18

61、_ connected to the moving tiller will bring the floating lever pivot and the lever into line at right angles to the screw shaft axis. (173369:第2 章船舶辅助机械(04 规则不考):1200) 查看备注查看答案

A. a cut-off lever

B. a cross-head

C.

a swivel block D.

a driving gear

62、the electronic governor actuator is a device which moves the fuel linkage in response to a signal from the digital controller.

A.pneumatic

B.hydraulic

C.electric

D.mechanical

63、switchboards may be of the dead-front type in which all live parts are installed behind _ and only the operation handles and instruments are on the front.

A.the collector

B.the surface

C.the capstan

D.the panels

64、To prevent the unnecessary loading of an air conditioning system while maintaining the designed dry bulb temperature and relative humidity in an air conditioning system, you should_ . (172898:第2 章船舶辅助机械:729) 查看备注查看答案

A. admit only enough fresh outside air to provide proper ventilation

B. reduce the air reheating system load

C. lower the compressor head pressure

D. operate the purge recovery unit continuously

65、In automatic __, the winch may be overhauled and wire is paid off the barrel at a pre-determined maximum tension.

A. Cranes

B.windlass

C.mooring winches

D. capstans

66、The effect that exhaust gas recirculation can reduce NOX formation is partly due to a reduction of the _ concentration in the combustion zone, and partly due to the content of water and carbon dioxide in the exhaust gas.

A.sulphur

B.freon

C.nitrogen

D.oxygen

67、The Convention prescribes_ _ relating to training, certification and watchkeeping for seafarers which countries are obliged to meet or exceed.

A.maximum standards

B.minimum startdards

C.mandatory stardards

D.recommended stardards

68、Which of the following operations need NOT to be entered on the O i l Record Book Part I? ①Routine discharge at sea of bilge water containing oil from the machinery spaces through strainers;②Bunkering of fuel oil. (174559:第4 章船舶轮机管理业务:581) 查看备注查看答案

A. ①only.

B. ②only.

C. Both ①and ②.

D. Neither ①nor ②.

69、speed engines operate in speed ranges from 300 to 1000 rpm.

A.Medium

B.High

C.Dead slow

D.Slow

70、Some pumps use packing as sealing gland. The gland should be _ _. (172615:第2章船舶辅助机械:446) 查看备注查看答案

A. slack enough to allow slight leakage of fluid

B. brought up tight so as not to allow any leakage

C. slightly clocked

D. fitted with a relief valve

71、At an unsheltered anchorage the chief engineer officer shall consult with whether or not to _ .

A.maintian an underway watch

B.take bunkering

C.clean

sea water filter D.do

engine repair work

72、where a centrifuge is arrange to separate two liquids, it is known as a _

A.liquid-separator

B.purifier

C.clarifier

D.oily water separator

73、Which of the routine maintenance procedure listed is required for starting air receivers? (171987:第1 章船舶主推进装置:1221) 查看备注查看答案

A. Frequent draining of accumulated moisture

B. Frequent testing of relief valves

C. A close watch on temperature to prevent fluctuations in pressure

D. Frequent cleaning to remove oil and foreign matter

74、some main diesel engines are fitted with , CO2 or steam extinguisher systems which should be utilized to extinguish fires in the scavenge spaces.

A.water

B.dry chemical

C.foam

D.1211

75、The frequency of an AC generator is adjusted by means of the _ __. (173496:第

3 章船舶电气和自动化:29) 查看备注查看答案

A. main alternator field rheostat

B. exciter field rheostat

C. prime mover governor control

D. equalizing reactor

This type of extinguisher contains a charge of sodium bicarbonate powder. The container of this type extinguisher holds a steel capsule containing liquid carbon dioxide. On breaking the capsule, by depressing the knob, the gas forces all the powder out of the discharge nozzle. The powder blankets the fire in a cloud of dust, cutting off the supply of oxygen. If the fire is hot enough the sodium bicarbonate will decompose to

form sodium carbonate, carbon dioxide and water all of which will aid the smothering operation and give some cooling effect. The extinguisher discharges in only 15 sec and it is thus important to aim the appliance accurately. The operating pressure of this container is higher than that of the soda-acid type. It is consequently hydraulically tested at a pressure of 35 bar.

1. What type of extinguisher does this paragraph talk about?

A. Dry power extinguisher

B. Carbon dioxide extinguisher

C. Foam extinguisher

D. Soda-acid extinguisher

2. Which of the following statements is not true?

A. Carbon dioxide in the capsule is used as an propellant.

B. When operating this extinguisher, we should break down the capsule.

C. The extinguisher should be turned upside down to depress the knob.

D. The blanketing agent is forced out.

3. According to this paragraph, the extinguishing principle of _ can be inferred.

A. covering the fire

B. cooling the temperature

C. smothering air

D. all of the above

4.This type of extinguisher can swiftly release the sodium bicarbonate powder in___ seconds.

A. 15

B. 35

C. 20

D. 50

During normal operation on heavy oil at sea, the oil is taken from the HO tanks, where it is stored. First, it is fed through a heater and next through a centrifuge for purification. It may then pass through a cooler, before being discharged to the steam-heated heavy oil service tanks. Two of these are usually fitted and they are used alternately. One tank is in use, while the other is being filled. These tanks are heated to a moderate temperature and self-closing drain valves are fitted to remove any water or sludge which may settle out. The oil is drawn from the service tank in use by pumps and discharged at low pressure to the fuel oil heater. These pumps should be in duplicate. A relief valve on the pumps will return excess pressure to the system. A viscosity regulator is fitted at the heater discharge, through which the oil will pass. This automatically controls the temperature of the oil fuel leaving the heater to maintain its viscosity within close limits. A by-pass must be fitted to the viscosity regulator. The oil is then discharged through a fine strainer to the main engine fuel pump suctions. A pressure control valve is fitted in the system and excess oil returned either to the heavy oil service tanks or to a balancing tank.

A diesel fuel tank is included in the system with its discharge to the primary pump suctions through a changeover valve. By operating this valve the engine may be operated on diesel oil. Changeover should be very gradual to allow temperature in the system to stabilize. During this period, the excess oil will return either to the heavy oil service tanks or a balancing tank. After it has been pumped from the DO tanks, where it is stored, the diesel oil passes through a centrifuge for purification before entering the diesel oil tank.

(1) Where are self-closing drain valves fitted?

A. HO tanks

B. Heavy oil service tanks

C. Balancing tank

D. centrifuge

(2) which of the following statements is true according to this passage?

A. Two heavy oil service tanks are used meanwhile.

B. ‘h eater’ mentioned in this passage is only used to heat heavy oil.

C.

Two pumps are fitted, which draw oil from the service tank in use.

D. Diesel oil passes to the primary pump, and then through a changeover valve.

(3)The word “these” in line 4 probably means __ .

A. HO tanks

B. a heater and a centrifuge

C. a heater and a cooler

D. heavy oil service tanks.

(4) How is change over from heavy oil to diesel oil carried out?

A. step by step

B. Hand over hand

C.step for step

D.Quickly

Many ships need only small amounts of steam at low pressure, and in these cases water

tube boilers can prove uneconomical. Of the variety of proprietary designs of fire tube or tank type boiler, many are composite, including sections for diesel exhaust gas heat recovery as well as for direct firing. In the Cochran boiler, the products of combustion and exhaust gases pass through separate sets of tubes immersed in the boiler water. These tubes are expanded into tube plate which form part of the boiler pressure shell. W ith the Aalborg AQ5 the gas streams pass horizontally over the outside of vertical tubes expanded into tube plates forming part of the boiler pressure vessel, in such a way that boiler water flows upwards throughout the tubes. Large downcomer tubes complete the circulation system. Larger Aalborg vertical fired boilers such as the AQ9, have water tube furnace enclosure walls and external downcomer. AG Weser produced a boiler unit where the products of combustion pass through tubes surrounded by boiler water whilst diesel exhaust passes over tubes through which boiler water passes.

A design similar in principle came from Howaldtswerke.

(1) In the AG Weser boiler mentioned in this passage .

1) the water is outside the tubes 2) The products of combustion is outside the tubes.

3)the diesel exhaust flows over the tubes

A.3)

B.1),2),3)

C.1),2)

D.2),3)

(2)with the Aalborg AQ5 boiler _. 1)the exhaust gas flows vertically 2)the gas is outside the tubes 3) boiler water flows upwards through the large downcomers

A.2)

B.3)

C.1)2)

D.1)2)3)

(3)In which cases that need small quantity of steams at low pressure?1) fire tube boilers are less economical than water tube one 2) water tube boilers are prohibited. 3) Water tube boilers are more welcome.

A.1),3)

B.1),2),3)

C.None of 1)2)3) is true

D.2)

(4)Composite boilers may mean those _ _ _.1) where either saturated or superheated steam is produces. 2) Combine a fire tube type and a water tube type. 3) Include sections for WHR and for oil firing oil

A.1),2),3)

B.3)

C.2),3)

D.1),2)

Circuit breakers must be capable of making an breaking under normal conditions and also abnormal conditions such as short circuit. As the circuit breaker must be able to withstand closing onto a fault conditions without sustaining damage, it is of heavy construction. Fitted with an over current release and overloads with time lags, a circuit breaker can be used as follows: to control the output of a generator , as a direct on-line starter and control outgoing feeder circuits.

On modern switchboards, “draw out”circuit breakers may be fitted. In the open position the whole circuit breaker can be wound clear of the bus bars, thus full inspection and maintenance can be achieved without the necessity of de-energizing the bus bars.

The “plug in” contacts joining the circuit breaker to the bus bars are not capable of taking before any attempt is made to withdraw it. A mechanical interlock is fitted arranged to trip the circuit breaker before the winding handle can be inserted.

The breaker also has a mid position. In this position the control circuits are still connected with the bus bar connection isolated. The electrical operation of the breaker can then be tested.

Circuit breakers are normally fitted with under voltage protection and tripping is accomplished by shorting, which releases the latching in mechanism. The no-volt coil may also be open circuited by a reverse power relay and an overload trip fitted with a time delay.

1. A circuit breaker can be used as follows except _ _.

A. to control outgoing feeder circuits

B. to act as a direct on line starter

C. to take the breaking load on line

D. to control the output of a generator

2. A “draw out” circuit breaker refers to a circuit breaker _.

A. which can be made clear of the bus bars by using a winding handle

B. which can be made clear of the bus bars by plugging in contacts

C. whose test can be carried out with the control circuit still connected

D. whose test can be carried out with the bus bar connection isolated

3. A mechanical interlock is fitted _.

A. to take the breaking load when the circuit breaker is being withdrawn

B. to put the circuit breaker, before being withdrawn, in the open position

C. to put the circuit breaker, before being withdrawn, in the mid position

D. to take the breaking load when the contacts join the circuit breaker to the bus bars

4. According to this passage, the electrical operation of this kind of circuit breaker can be tested when _.

A. the control circuits are connected

B. the bus bar connection is isolated

C. either A or B

D. both A and B

参考答案

ACDCA ADCBA DCBAD BDDBC CCBDA ADADC BACBD CAACB

BBDCA CDAAC ABBBB CAACA ACDAD CBDAA ABACC

ACDA BCDA BADC CABD