不规则动词表

最新不规则动词练习题

精品文档 用所给单词的适当形式填空。 1.On March 3rd, 1866, Powell _________ (ride) his horse down the mountain toward the valley. 2.I _________ (be) very busy these days since my husband _________ (go) abroad for his two-year study. 3.Scotland's radio stations _________ (lose) tens of thousands of listeners last year. 4.Zhen Zhe _________ (grow) up in Changchun, the capital of Jilin Province, located in northeast China. 5. The photos _________ (take) many years ago _________ (lose) last week. 6.Hardly had the match ________ (begin) when Jack ________ (get) his legs ________ (break) . 7.Several trees ________ (blow) down in the storm and the ________ (fall) branches and leaves were everywhere. 8.A new house ________ (build) at present after the old one ________ (burn) down by an unexpected fire. 9.The thief ________ (flee) from the police station but ________ (catch) again only three hours later. 10.With all they needed ________ (buy) , the Smiths ________ (drive) back home. 11.He ________ (dig) his fork into the meat and ________ (eat) it up at a mouthful. 12.When Jack ________ (swim) halfway, he ________ (meet) with a troop of sharks, and his life ________ (come) to an end. 13.The missing girl ________ (say) evidently just now ________ (see) picking flowers near the river. 14.You ________ (keep) breaking the club rules, so you ________ (throw) out if you 精品文档． 精品文档 lose the last opportunity. 15.None of us ________ (know) her address at that time. If we ________ (know) it, we ________ (send) her a note. 16.________ (keep) at the bottom of the case for so long, the letter ________ (forget) so far. 17.She ________ (mistake) for the famous singer because she ________ (sing) the songs alike. 18.The days are ________ (go) when we played all day and ________ (sleep) all night. 19.________ (speak) English is somewhat different from ________ (write) English, which ________ (go) more normally. 20.The moon ________ (rise) slowly and the mountainous village ________ (lie) in mysterious light and silence.

英语常用不规则动词表完整版打印版

英语常用不规则动词正版完整版 一、规则动词的过去式由“动词原形+-ed”构成，具体变化有： 1. 直接在词尾加-ed。如: want—wanted, work—worked, need—needed, clean—cleaned 2. 以不发音的e结尾的在词尾加-d。如：like—liked, live—lived, use—used, move—moved 3. 以一个元音字母加一个辅音字母结尾的重读闭音节动词，先双写结尾的辅音字母，再加-ed。如：stop—stopped, trip—tripped 4. 以辅音字母加y结尾的动词，先把y变成i，再加-ed。如：study—studied, carry—carried, hurry—hurried, marry—married 二、不规则动词变化，大体上归纳有以下六条记忆法： 1. 以t结尾的词，过去式与原形相同。如：put—put, let—let, cut—cut, beat—beat 2. 以d结尾的词，把d变成t。如:build—built, lend—lent, send—sent, spend—spent 3. 以n结尾的词，在词后加t。如：mean—meant, burn—burnt, learn—learnt 4. 以ow / aw结尾的词，把ow / aw变成ew。如：blow—blew, draw—drew, know—knew, grow—grew 5. 含有双写字母的词，将双写改为单写，在词尾加t。如：keep—kept, sleep—slept, feel—felt, smell—smelt 6. 含有元音字母o / i的词，将o / i变成a。如：sing—sang, give—gave, sit—sat, drink—drank 1.AAA 动词原形过去式过去分词现在分词词义 bet bet bet betting 赌 broadcast broadcast broadcast ~ 广播.播放.播送 burst burst burst ~ 爆炸.突然发作 cast cast cast 抛 cost cost cost ~ 花费 cut cut cut cutting 割，切 forecast forecast/forecasted forecast/forecasted 预测，预报 hurt hurt hurt ~ 受伤 hit hit hit hitting 打，撞 let let let letting 让 put put put putting 放下 read read read ~ 读 rid rid rid ridding 使摆脱.使去掉 saw sawed sawed / sawn ~ 锯 set set set setting 安排，安置 spread spread spread ~ 展开，传播，涂 spit spat spat spitting 吐痰, shut shut shut shutting 关上.停止营业 split split split splitting 使分裂（成不同的派别），分开，分担，分摊 spread spread spread 传播，扩散，展开，散布quit quit / quitted quit / quitted 放弃

高考不规则动词表检测单

高考不规则动词表----- 检测单 过去式，过去分词，现在分词，汉语 1，arise ___________ ___________ _________ 2, awake ___________ ___________ _________ 3, bear ___________ ___________ _________ 4, beat ___________ ___________ _________ 5，become___________ ___________ _________ 6, begin___________ ___________ _________ 7, bend___________ ___________ _________ 8, bid___________ ___________ _________ 9, bite___________ ___________ _________ 10, bleed___________ ___________ _________ 11, blow___________ ___________ _________ 12, break___________ ___________ _________ 13, bring___________ ___________ _________ 14, broadcast___________ ___________ _________ 15, build___________ ___________ _________ 16, burn___________ ___________ _________ 17, burst___________ ___________ _________ 18, buy___________ ___________ _________ 19, catch___________ ___________ _________ 20, choose___________ ___________ _________ 21, come___________ ___________ _________

不规则动词测试题

高中英语常用不规则动词表 1. AAA型（动词原形、过去式、过去分词同形） bet 打赌_______ _______ broadcast广播__________ _________ burst 爆发_______ _______ cast 抛_______ _______ cost 花费_______ _______ cut 切_______ _______ hit 打_______ _______ hurt 伤害_______ _______ let让_______ _______ put 放_______ _______ read读_______ _______ set树立，点燃_______ _______ shut关闭_______ _______ spread传播_______ _______ quit放弃_______ _______ spit 吐出_______ _______ upset _______ _______ wet弄湿_______ _______ 2. AAB型（动词原形与过去式同形） beat打_______ _______ 3. ABA型（动词原形与过去分词同形） become变_______ _______ come来_______ _______ run跑_______ _______ overcome 克服_________ _______ 4. ABB型（过去式与过去分词同形） bend弯曲，屈服_______ _______ bring带来_______ _______ build建设_______ _______ burn 燃烧_______ _______ buy买_______ _______ catch抓住_______ _______ deal处理_______ _______ dig挖_______ _______ dream 做梦_______ _______，feed饲养_______ _______ feel感觉_______ _______ fight战斗_______ _______ find找到_______ _______ flee逃跑_______ _______ get得到_______ _______ hang绞死_______ _______ hang（悬挂）_______ _______ have / has有_______ _______ hear听见_______ _______ hold抓住_______ _______ keep保持_______ _______ lay产卵_______ _______ lead领导，导致_______ _______ learn学习_______ _______ leave离开_______ _______lend借出_______ _______ light 点燃_______ _______ lose丢失_______ _______ make制造_______ _______ mean意思是_______ _______ meet遇见_______ _______ pay支付_______ _______ prove证明_______ _______ quit放弃，停止_______ _______rebuild 重建_______ _______retell复述_______ _______ say说_______ _______ seek寻找_______ _______ sell卖_______ _______ send发送，派遣_______ _______sew缝_______ _______ shine照耀_______ _______ shoot射击_______ _______ sit坐_______ _______ sleep睡_______ _______ slide滑动_______ _______ smell闻_______ _______ sow播种_______ _______ speed 加速_______ _______ spell拼写_______ _______spend 花费_______ _______

六年级不规则动词表答案

六年级不规则动词表 1.am, is-was 2.are-were 3.become-became 4.begin-began 5.bend-bent 6.blow-blew 7.break-broke 8.bring-brought 9.build-built 10.buy-bought 11.can-could https://www.360docs.net/doc/d610556297.html,e-came 13.cut-cut 14.dig-dug 15.do-did 16.draw-drew 17.dream-dreamt 18.drink-drank 19.drive-drove 20.eat-ate 21.fall-fell 22.feed-fed 23.feel-felt 24.fly-flew 25.get-got 26.give-gave 27.go-went 28.grow-grew 29.have, has-had 30.hear-heard 31.hit-hit 32.hold-held 33.hurt-hurt 34.keep-kept 35.know-knew 36.learn-learnt 37.leave-left 38.let-let 39.make-made 40.may-might 41.mean-meant 42.meet-met 43.put-put 44.read-read 45.ride-rode 46.ring-rang 47.run-ran 48.say-said 49.see-saw 50.sell-sold 51.set-set 52.shake-shook 53.shall-should 54.shut-shut 55.sing-sang 56.sit-sat 57.sleep-slept 58.smell-smelt 59.speak-spoke 60.spell-spelt 61.spend-spent 62.stand-stood 63.swim-swam 64.take -took 65.teach-taught 66.tell-told 67.think-thought 68.understand-understo od 69.wear-wore 70.will-would 71.win -won

(完整)小学六年级英语常用不规则动词的过去式练习

常用不规则动词的过去式练习

Am / is---_______(是) are---_______（是） become---_______（变成）bear---_______（忍受） begin---_______（开始） break---_______（打破）buy---_______（买）bring---_______（带来）build---_______（建设）can---_______（能，会）come---_______（来） catch---_______（抓住）cost---_______（花费） cut---_______（砍，切） do / does---_______（做） drink---_______（喝） eat---_______（吃）drive---_______（开 车） feel---_______（感觉） fly---_______（飞行） find---_______（发现，找到） forget---_______（忘记） get---_______（得到） give---_______（给予）go---_______（走，去） have / has---_______（有）grow---_______（成长，种） hear---_______（听见） lend---_______（借给） know---_______（知道）leave---_______（离开，留下） let---_______（让）learn---_______（学习）lie---_______（躺下）lose---_______（丢失） make---_______（制作）meet---_______（遇见） may---_______（可以）must---_______（必须）pay---_______（付钱，赔偿）put---_______（放） read---_______（读）ride---_______（骑，乘） run---_______（跑）ring---_______（钟§铃响） say---_______（说） see---_______（看见） sell---_______（卖）shall---_______（将）sing---_______（唱） sit---_______（坐） sleep---_______（睡） smell---_______（嗅，闻） speak---_______（说）stand---_______（站） swim---_______（游泳） spell---_______（拼写）teach---_______（教） wear---_______（穿戴）take---_______（带， 乘）

(完整word版)高中英语不规则动词表.doc

高中英语不规则动词表 王艳英 一、规则动词的过去式由“动词原形+-ed ”构成，具体变化有： 1. 直接在词尾加 -ed 。如 : want — wanted, work — worked, need —needed, clean — cleaned 2. 以不发音的 e 结尾的在词尾加 -d。如： like—liked, live —lived, use —used, move —moved 3.以一个元音字母加一个辅音字母结尾的重读闭音节动词，先双写结尾的辅音 字母，再加 -ed 。如： stop —stopped, trip —tripped 4.以辅音字母加 y 结尾的动词，先把 y 变成 i，再加 -ed 。如： study —studied, carry —carried, hurry — hurried, marry —married 二、不规则动词变化，大体上归纳有以下六条记忆法： 1.以 t 结尾的词，过去式与原形相同。如：put —put, let — let, cut — cut, beat —beat 2.以 d 结尾的词，把 d 变成 t 。如 :build —built, lend —lent, send —sent, spend —spent 3.以 n 结尾的词，在词后加 t。如： mean — meant, burn —burnt, learn —learnt 4.以 ow / aw 结尾的词，把 ow / aw 变成 ew 。如： blow — blew, draw —drew, know — knew, grow — grew 5.含有双写字母的词，将双写改为单写，在词尾加t。如：keep—kept, sleep — slept, feel — felt, smell — smelt 6. 含有元音字母 o / i 的词，将 o / i 变成 a。如：sing —sang, give —gave, sit —sat, drink —drank 三、不规则动词表 动词原形中文意思过去式过去分词 arise 出现arose arisen awake 醒来awoke awaked / awoken baby-sit 临时照顾baby-sat baby-sat be(am / is / are) 是was / were been beat 击打beat beaten become 变成became become

常见不规则动词变化表

( 原形→过去式→过去分词)

常见动词用法辨析 (1)“Why not+动词原形+…?”(干嘛不……?)是简略句,完全形式是：Why don’t you+ 动词原形+…?如：Why not go and have a look?(干嘛不去看看？)/ Why not try it once again?(为什么不再试试？) (2) seem(好象)的用法：记住几个结构：①sb./sth. + seem + (to be+)形容词+…； ②sb./sth. + seem + like +…；③sb/sth + seem + to (do)；④It seems that + 从句。如：He seemed (to be) very happy when he was called by the headmaster. (被校长叫到名字时他好象很开心) / It seems that nobody else could do such a foolish thing except Jim. (除了吉姆好象没有什么人会做出如此愚蠢的事情 来) (3)be afraid(害怕)的用法：记住几个结构：①be afraid of sth; be afraid of (doing); ②be afraid to (do); ③be afraid that+从句。如：She is a little afraid of snakes.(她有点怕蛇)/ Don’t be so afraid to stay at home alone at night.(别害怕晚上一个人在家)/ I’m afraid that somebody will take his place because of his serious mistakes.(恐怕有人要取代他了,因为他犯了那么大的错误) (4) be sorry(抱歉)的用法：记住几个结构：①be sorry for (sth); ②be sorry for (doing sth); ③be sorry to (do); ④be sorry that+从句。如：I am very sorry for keeping you waiting so long.(不好意思让你久等了)I am sorry to trouble you.(对不起,麻烦你了)/ I am sorry (that) he isn’t here at the moment.(恐怕他现在不在) (5)be sure (确信)的用法：记住几个结构：①be sure of (sth); ②be sure to(do); ③be sure that+从句。如：She told me many times that she was sure to come.(她 给我讲过多次她一定会来的) / Are you sure of your answer?Maybe it’s wrong.(你对你的答案有把握吗？也许是错的。)/ I am sure that Dad will help me with the job.(我确信爸爸会帮着我做这件事情的) (6) make与do的用法：一般情况下表示进行活动或者做工作用do,表示创造建构某事 物用make.如：I don’t know what to do.(我不知道该干什么)/ I’m not going to do any work.(我不准备做什么)/ My father and I once made a boat.(我和我爸曾经做过一只船) 此外还要记住一些固定说法：do good / harm / business / one’s best / a favour……

英语不规则动词表(完整版)

1.规则动词：规则动词的过去分词的构成规则与规则 动词的过去式的构成规则相同。四点变化规则： (1)、一般动词，在词尾直接加“ ed ”。（然而要注意 的是，过去分词并不是过去式）； work---worked---worked ,visit---visited---visited (2)、以“ e ”结尾的动词，只在词尾加“ d ”； live---lived---lived , (3)、以“辅音字母 + y ”结尾的动词，将 "y" 变为 "i" ， 再加“ ed ”； study---studied---studied ,cry---cried---cried 除了a、e、i、o、u，其余都是辅音： b、c、d、f、g、h、j、k、l、m、n、p、q、r、s、 t、v、w、x、y、z (4)、重读闭音节结尾，末尾只有一个辅音字母，先双 写该辅音字母，再加“ ed ”。 stop---stopped---stopped , drop---dropped-- dropped 单元音： [i:][i][e][?][a:][?] [?:][u][u:] [?][?:][?] 双元音： [ei][ai][?i][?u] [au][i?][ε?][u?] 辅音： [p][b][t][d] [k][g][f][v] [s][z][θ][δ] [∫] [з][t∫][dз] [tr] [dr] [ts] [dz] [m][n][?][h] [l][r][w][j] 2.不规则动词表（如下） 一、A—A—A型，即原形、过去式和过去分词三 者都相同。（共7个） cost—cost—cost cut—cut—cut hit—hit—hit hurt—hurt—hurt let—let—let put—put—put read— read—read 二、A—B—B型，即过去式、过去分词相同。 （共41个） 1.过去式和过去分词都含有 -ought。（4个）bring—brought—brought buy—bought—bought think—thought—thought fight-fought-fought 2.词尾有-ild，-end时，只需把d变为t。（4个） build—built—built lend—lent— lent send—sent—sent spend—spent— spent 3．过去式、过去分词都含有 -aught。（2个） catch—caught—caught teach—taught—taught 4．把-eep变为-ept。（3个） keep—kept—kept sleep—slept—slept sweep— swept—swept 5.把-ell变为-old。（2个） tell—told—told sell—sold—sold 6．过去式、过去分词都含有-elt或-ilt。（4个） smell—smelt—smelt spell—spelt—spelt feel—felt— felt spill—spilt—spilt 7．过去式、过去分词都在原形词尾加t。（3个） learn—learnt—learnt mean—meant—meant spoil—spoilt—spoilt 8．过去式、过去分词词尾去y变-id（4个） say—said—said pay—paid—paid lay—laid—laid hear—heard—heard 9．改变元音字母。（11个） meet—met—met get—got—got sit—sat—sat find—found—found hold—held—held spit—spat— spat shine—shone—shone win—won—won hang—hung—hung dig— dug—dug lose—lost—lost 10．改变辅音字母。（1个） make—made—made 11.改变元、辅音字母。（4个） leave—left—left stand—stood—stood have（has）— had—had understand—understood—understood 三、A—B—C型，即原形、过去式、过去分词都 不相同。（共35个） 1．i—a—u变化。（6个） begin—began—begun drink—drank—drunk sing— sang—sung ring—rang—rung swim—swam—swum sink— sank—sunk 2．词尾为-ow，-aw时，过去式将其变为-ew，过 去分词在其原形后加n。（5个） blow—blew—blown draw—drew—drawn grow— grew—grown know—knew—known throw—threw—thrown（show除外） 3．词尾为“i+辅（1个）+e”，过去式将i变为o， 过去分词多在原形后加n，若那个辅音字母为d或t， 须双写d或t后加n。（4个）（give，hide除外）drive—drove—driven write—wrote—written ride— rode—ridden rise—rose—risen 4．过去分词在过去式后加（e）n。（5个） break—broke—broken choose—chose—chosen freeze—froze—frozen speak—spoke—spoken wake—woke— woken 5．过去分词由过去式加-ten构成。（1个） forget—forgot—forgotten 6．过去分词由原形加（e）n构成。（6个） be—was（were）—been eat—ate—eaten fall—fell—fallen give—gave—given see—saw—seen hide—hid—hidden（hid）

初中英语不规则动词表及测试卷.doc

初中英语不规则动词表（一） 一、 AAA型（原形→原形→原形） 原形过去式过去分词汉语意思 read read read 读 cut cut cut 切，割 let let let 让 put put put 放 cost cost cost 花费，值hit hit hit 撞，击 set set set 安排，安置hurt hurt hurt 使伤痛 二、 ABA型（原形→过去式→原形） 原形过去式过去分词汉语意思become became become 成为come came come 来 run ran run 跑 三、 ABC型 1. ow → ew →own 原形过去式过去分词汉语意思blow blew blown 吹 draw drew drawn 画 grow grew grown 生长know knew known 知道 fly flew flown 飞 2. i →a →u 原形过去式过去分词汉语意思begin began begun 开始drink drank drunk 喝 sing sang sung 唱 swim swam swum 游泳 ring rang rung 打电话3.原形→过去式→过去式 +(e)n

wear wore worn 穿forget forgot forgotten 忘记speak spoke spoken 说freeze froze frozen 冻choose chose chosen 选择 4.原形→过去式→原形 +(e)n 原形过去式过去分词汉语意思eat ate eaten 吃forbid forbade forbidden 禁止give gave given 给 ride rode ridden 骑 see saw seen 看见write wrote written 写 fall fell fallen 落下 5. 无规律 原形过去式过去分词汉语意思am/is was been 是 are were been 是 do did done 做 go went gone 走 take took taken 拿 四、 ABB型 1. 原形→ought →ought 原形过去式过去分词汉语意思bring brought brought 带来buy bought bought 买 fight fought fought 打架think thought thought 思考 2.原形→aught→aught

常用不规则动词表小学版

常用不规则动词表 动词原形过去式过去分词be was/were been 是beat beat beaten 打become became become 变begin began begun 开始blow blew blown 吹break broke broken 破bring brought broght带来build built built建筑buy bought bought买catch caught caught捉come came come来cost cost cost花费 cut cut cut割 dig dug dug挖 do did done做 draw drew drawn画 dream dreamed dreamed梦 dreamt dreamt梦 drink drank drunk 喝

drive drove driven驾驶eat ate eaten吃 feel felt felt感觉 fight fought fought战斗find found found发现 fly flew flown飞 forget forgot forgotten忘记forgive forgave forgiven原谅get got got得到 give gave given给 go went gone去 have had had有 hear heard heard 听 hold held held持 hurt hurt hurt损伤keep kept kept保持know knew known知道learn learnt learnt学习leave left left离开 let let let让 lose lost lost失去

不规则动词表完整版

. freeze froze冻frozen英语不规则动词归类表chosenchose选择choose原形→原形）一、AAA型（原形→woken 醒wake woke bitten bit 咬bite 意思原形过去式过去分词get got 得到got/gotten readread read读forget forgot forgotten 忘记cutcut cut切，割hidden hide hid 隐藏letlet let让

stole stolen 偷steal put put put放awake awoke awoken 醒cost cost cost花费，值sworn swear swore 发誓hithithit撞，击tore torn 撕，扯tear set set set安置安排，weave wove woven 织，编spreadspread spread散布传播，+(e)n原形4. 原形→过去式→hurt hurt hurt 使…伤痛 意思原形过去式过去分词 shut shut shut 关吃eat ate eaten bid bid bid 出价禁止forbid forbidden forbade burst burst burst 破裂give gave given给cast cast cast 投，掷ride rode ridden骑[ka:st]saw seen看见see rid rid rid 摆脱wrote written写write[rid] fell fallen fall shed shed shed 落下流出，脱ed][落?arisen arise arose slit slit slit )被升起(撕开切开，split split split 劈开裂开，rise risen rose )主动升起(thrust thrust thrust刺，戳][θr?st画drew drawn draw 原形）型（原形ABA →过去式→二、 意思原形过去式过去分词驾驶drove drive driven 成为becomebecame become comecame come来误会mistake mistook mistaken run run跑ran overcame overcome overcome 克服拿走took take taken三AB摇shook shake shaken

不规则动词练习问题详解

2. A dam burst and flooded their villages.堤坝决口，淹没了他们的村庄。 3. Careless driving cost him his life.开车不小心使他丧了命。 4. You've had your hair cut, it looks great.你理发了，看上去不错。 5. He is afraid of hurting Bessy's feelings.他怕伤害了贝茜的感情。 6. Police at the scene said Dr Mahgoub had been hit several times in the head.现场的警察称马哈古卜医生的头部遭到了几次击打。 7. Let me suggest an alternative.请允许我阐述另一种可能。 8. She hesitated, then put her hand on Grace's arm.她犹豫了一下，然后把手放到格雷斯的胳膊上。 9. He read through the pages slowly and carefully.他慢慢地仔细阅读每一页。 10. That's why we're getting rid of regulations that don't work.这就是为什么我们要摆脱无用的规定。 11. Bob set us a good example.鲍伯为我们树立了一个好榜样。 12. In his room, Tom was spreading out a map of Scandinavia on the bed.房间里，汤姆正将一张斯堪的纳维亚地图在床上铺开。 13. They spat at me and laughed at me.他们朝我吐唾沫，还嘲笑我。 I felt my heart beating faster.我感觉我的心越跳越快。 During the 1980s the world's financial systems became more open.在20世纪80年代，世界金融体系变得更加开放。 17. He came to a door that led into a passageway.他来到一扇门前，这扇门通往一条走廊。 18. Neighbouring shopkeepers ran after the man and caught him.附近的店主在那个男人后面追赶并把他抓住了。

不规则动词表完整版

不规则动词表完整版 不定式(Infinitive) 意思过去式 (Past Tense) 过去分词 (Past Participle) abide 居住abode, abided abode, abided alight 下车alighted, alit alighted, alit arise 起来arose arisen awake 唤醒awoke awoke, awaked be 是was, were been bear 忍受bore borne, born beat 击打beat beaten become 变成became become befall 发生befell befallen beget 引起begot begotten, begot begin 开始began begun behold 注意看beheld beheld bend 鞠躬bent bent bereave 剥夺bereaved, bereft bereaved, bereft beseech 乞求besought, beseeched besought, beseeched beset 围攻beset beset bespeak 预约bespoke bespoken, bespoke bespread 铺盖bespread bespread bestrew 散放bestrewed bestrewed, bestrewn bestride 跨坐bestrode bestridden, bestrid, bestrode bet 打赌bet, betted bet, betted betake 前往betook betaken bethink 想起bethought bethought bid 出价bade, bid bidden, bid bide 忍受bode, bided bided bind 绑bound bound bite 咬bit bitten, bit bleed 流血bled bled blend 混合blended, blent blended, blent bless 祝福blessed, blest blessed, blest blow 吹blew blown break 断开broke broken breed 产生bred bred bring 带来brought brought broadcast 广播broadcast, broadcasted broadcast, broadcasted browbeat 严斥browbeat browbeaten build 建筑built built burn 燃烧burnt, burned burnt, burned burst 爆炸burst burst buy 买bought bought