- a line on the surface of something along which it has split without breaking into separate parts裂缝; 裂口; 裂纹：
a hairline crack down the middle of the glass
玻璃杯的中下部的一条极细的裂缝。
- a narrow space between two surfaces, especially ones which have broken or been moved apart缝隙：
he climbed into a crack between two rocks
他爬进两块岩石间的缝隙中
the door opened a tiny crack.
门开了一条小缝。
- figurative a vulnerable point; a flaw〈喻〉瑕疵, 脆弱点, 缺点：
the company spotted a crack in their rival's defences.
公司发现了他们对手的答辩中有个漏洞。
- a sudden sharp or explosive noise爆裂声; 噼啪声：
a loud crack of thunder
一声霹雳。
- a sharp blow, especially one which makes a noise（尤指发出响声的）猛烈一击：
she gave the thief a crack over the head with her rolling pin.
她用擀面杖猛击小偷的头部。
- a sudden harshness or change in pitch in a person's voice（人的嗓音的）突然变化; 变粗, 变哑：
the boy's voice had an uncertain crack in it.
这个男孩的嗓音不知怎么发生了突然变化。
- informal a joke, typically a critical or unkind one〈非正式〉笑话; 俏皮话; 挖苦话。
- Scottish & N. English a conversation〈苏格兰, 北英格兰〉聊天; 谈话：
they are having a great crack about shooting.
他们在起劲地聊射击呢。
- （亦作 craic）[mass noun] Irish enjoyable entertainment or activity; a good time〈爱尔兰〉令人愉快的演出（或活动）; 开心的时间：
he loved the crack, the laughing.
他喜欢尽情地玩, 笑声使他愉快。
- in sing. informal attempt to gain or achieve something〈非正式〉尝试：
I fancy having a crack at winning a fourth title.
我想试试是否能第四次夺冠。
- a chance to attack or compete with someone进攻机会; 竞争机会：
he wanted to have a crack at the enemy.
他希望有机会对敌人发起进攻。
- （亦作 crack cocaine）[mass noun] a potent hard crystalline form of cocaine broken into small pieces and inhaled or smoked强效纯可卡因。
- break or cause to break without a complete separation of the parts（使）爆裂; （使）破裂：
no obj. the ice all over the bog had cracked沼泽地区的冰都开裂了
with obj. take care not to crack the glass.小心别将玻璃弄裂了。
- break or cause to break open or apart（使）断裂（或断开）：
no obj., with adverbial a chunk of the cliff had cracked off in a storm一大块悬崖在暴风雨中断开并倒落了下来
figurative 〈喻〉his face cracked into a smile
他笑得合不拢嘴
with obj. she cracked an egg into the frying pan.她将一个鸡蛋打入了煎锅。
- with obj. break (wheat or corn) into coarse pieces将（小麦或谷物）粗磨。
- figurative give way or cause to give way under torture, pressure, or strain〈喻〉（使）屈服：
no obj. the witnesses cracked and the truth came out证人屈服了, 真相被透露了出来
with obj. no one can crack them - they believe their cover story.没有人能使他们屈服——他们相信自己编造的故事。
- no obj.
crack up
informal suffer an emotional breakdown under pressure〈非正式〉（在压力下）感情崩溃。
- no obj.
crack up
informal burst into laughter〈非正式〉大笑起来。
- make or cause to make a sudden sharp or explosive sound（使）发出噼啪（或爆裂）声：
no obj. a shot cracked across the ridge山脉的那边响起了一声枪声
with obj. he cracked his whip and galloped away.他甩了个响鞭, 骑马飞驰而去。
- no obj. knock against something, making a noise on impact（发出声音地）撞击：
she winced as her knees cracked against metal.
她因膝盖撞上了金属而面露痛苦万状。
- with obj. hit (someone or something) hard, making a sharp noise猛烈地击打：
she cracked him across the forehead.
她猛击他的前额。
- no obj.(of a person's voice, especially that of an adolescent boy or a person under strain) suddenly change in pitch（尤指青春期的男孩或成人在压力下）变声, 声音变粗, 变哑：
'I want to get away,' she said, her voice cracking.
她嗓音嘶哑地说道, “我想走了。”
- with obj. informal find a solution to; decipher or interpret〈非正式〉解决; 破译; 解释：
the code will help you crack the messages.
这个密码可以帮助你破译这些信息。
- break into (a safe)砸开（保险箱）。
- succeed in achieving成功获得：
he cracked a brilliant goal.
他达到了很高的目标。
- with obj. decompose (hydrocarbons) by heat and pressure with or without a catalyst to produce lighter hydrocarbons, especially in oil refining（尤指炼油中）使（碳氢化合物）裂化, 使分解：
as noun cracking catalytic cracking催化裂化。
- very good, especially at a specified activity or in a specified role（尤指在某方面）顶呱呱的, 第一流的, 非常棒的：
he is a crack shot
他是个一流的射击手
crack troops
精锐部队。
crack a book
- N. Amer. informal open a book and read it; study〈北美, 非正式〉打开书本读书; 学习。
crack a bottle
- open a bottle, especially of wine, and drink it开瓶喝酒（或喝饮料）。
crack a crib
- Brit. archaic, informal break into a house〈英, 古, 非正式〉破门而入。
crack of dawn
- a time very early in the morning; daybreak黎明; 拂晓。
crack of doom
- a thunder peal announcing the Day of Judgement世界末日的霹雳。
crack of the whip
- Brit. informal a chance to try one's hand at or participate in something〈英, 非正式〉尝试机会; 参与机会：
individuals who feel that they have not had a fair crack of the whip
感到没有取得公平参与机会的个人。
cracked up to be
- with negative informal asserted to be (used to indicate that someone or something has been described too favourably)〈非正式〉所称（或所说）的那么好（用于表示某人或某事物被说得太好了）：
life on tour is not as glamorous as it's cracked up to be.
旅行生活并不像所说的那样迷人。
crack wise
- N. Amer. informal make jokes〈北美, 非正式〉开玩笑, 说笑话。
get cracking
- informal act quickly and energetically〈非正式〉迅速行动起来：
most tickets have been snapped up, so get cracking if you want one.
大部分门票已被抢购一空; 所以, 如果你想弄一张的话, 得赶快行动了。
slip（或 fall）through the cracks
- N. Amer. another way of saying slip through the net.〈北美〉 同 slip through the net. （见NET1）.
crack down on
- informal take severe measures against〈非正式〉对…采取严厉措施; 镇压; 制裁：
we need to crack down hard on workplaces that break safety regulations.
我们必须严惩不守安全规则的工场。
crack on
- informal proceed or progress quickly〈非正式〉加劲干; 迅速进行：
we'll crack on with the second half of the job this month.
这个月我们要加快后半部分工作的进程。