/kræk; kræk/
n
1 ~ (in sth)
(a) line along which sth has broken, but not into separate parts 裂缝; 裂纹
*a cup with bad cracks in it 有很多裂纹的杯子
* Don't go skating today there are dangerous cracks in the ice. 今天别去溜冰了--冰上有裂缝很危险.
* (fig 比喻) The cracks (ie defects) in the Government's economic policy are beginning to show. 政府经济政策上的失误已渐渐明显. =>illus at chip 见chip之插图.
(b) narrow opening 缝隙
*She looked through a crack in the curtains. 她透过帘子的缝隙观望.
* Open the door a crack, ie Open it very slightly. 把门打开一条缝（打开一点点）.
2 sudden sharp noise 爆裂声; 　啪声
*the crack of a pistol shot 　　啪啪的手枪声
* a crack of thunder 一声霹雳.
3 ~ (on sth) sharp blow, usu one that can be heard 重击（通常为可听到响声的）
*give sb/get a crack on the head 吧的一声打在某人的头上[头上挨了一下子].
4 ~ (about sth) (infml 口) clever and amusing remark, often critical; joke 俏皮话（常为挖苦人的）; 笑话
*She made a crack about his fatness. 她取笑他肥胖.
5 ~ at sth/doing sth (infml 口) attempt at sth 试做某事物
*Have another crack at solving this puzzle. 再试一试把这个难题解决了吧.
6 (idm 习语) the crack of `dawn (infml 口) very early in the morning 黎明; 破晓
*get up at the crack of dawn 黎明即起. the crack of `doom the end of the world 世界末日
* (fig 比喻) To get a bus here you have to wait till the crack of doom, ie an extremely long time. 在这儿真要等到世界末日（很久很久以後）才能有公共汽车. a fair crack of the whip => fair1. paper over the cracks => paper.

adj [attrib 作定语] very clever or expert; excellent 精明能干的; 技艺高超的; 优秀的
*a crack regiment 劲旅
* He's a crack shot, ie expert at shooting. 他是神枪手.

/kræk; kræk/
v
1 [I, Tn] (cause to) develop a crack1(1a) or cracks （使）开裂, 破裂, 爆裂
*The ice cracked as I stepped onto it. 我一踩冰就裂了.
* You can crack this toughened glass, but you can't break it. 这种韧化玻璃只裂不碎.
* She has cracked a bone in her arm. 她手臂有一处骨裂.
* a cracked mug 有裂纹的缸子.
2 [Tn, Cn.a] break (sth) open or into pieces 砸开或砸碎（某物）
*crack a nut 把坚果砸碎
* crack a safe, ie open it to steal from it 砸开保险箱
* crack a casing open 　里啪啦打开包装.
3 [Tn, Tn.pr] sth (on/against sth) hit sth sharply 猛击某物
*I cracked my head on the low door-frame. 我的头撞在低矮的门框上了.
4 [I, Tn no passive 不用于被动语态] (cause sth to) make a sharp sound （使某物）发出爆裂声; （使某物）　啪作响
*crack a whip, one's knuckles 抽鞭子、屈指节　啪作响
* The hunter's rifle cracked and the deer fell dead. 猎人的枪一响, 鹿即倒地而死.
5 [I, Tn] (cause sb to) cease to resist; (cause sth to) fail （使某人）屈服; （使某事物）垮台
*The suspect cracked under questioning. 嫌疑分子在审问之下招供了.
* They finally cracked the defence and scored a goal. 他们终于突破了防守, 射进一球.
6 [Tn] (infml 口) solve (a problem, etc) 解决（问题等）
*The calculation was difficult, but we finally cracked it. 计算起来很费劲, 然而我们终于解决了.
* crack a code, ie decipher it 破译密码.
7 [I] (of the voice) change in depth, loudness, etc suddenly and uncontrollably （指嗓音）突然而失控地改变音色、音量等
*In a voice cracking with emotion, he announced the death of his father. 他悲恸失声地宣布了父亲去世的消息.
* A boy's voice cracks (ie becomes deeper) at puberty. 男孩在青春期嗓音改变（声音变粗）.
8 [Tn] (infml 口) open (a bottle, esp of alcoholic drink) and drink its contents 开（瓶, 尤指酒瓶）饮用.
9 [Tn] (infml 口) tell (a joke) 说（笑话）.
10 [Tn] (chemistry 化) break down (heavy oils) by heat and pressure to produce lighter oils 使裂化（利用高温高压从质量较重的石油里制取轻油）.
11 (idm 习语) cracked `up to be sth (usu negative 通常作否定) (infml 口) reputed to be sth 号称
*He's not such a good writer as he's cracked up to be. 他并不像人们所吹捧的那样是什么杰出的作家. get `cracking (infml 口) begin, esp energetically 开始; （尤指）大干起来
*There's a lot to be done, so let's get cracking. 工作很多, 咱们开始干吧.
12 (phr v) crack down (on sb/sth) impose more severe treatment or restrictions on sb/sth （对某人[某事物]）严加处置或限制
*Police are cracking down on drug dealers. 警方现对贩毒分子严惩不贷. crack up (infml 口) lose one's physical or mental health （身体）垮掉; （精神）崩溃
*You'll crack up if you go on working so hard. 你继续这样拚命干下去, 身体会吃不消的.