21.be short of hands 缺乏人手，人手不够
short作表语时指“某物不够，缺乏某物”的意思，常与介词of搭配使用，既短语be short of something。
a: you look worried about something. what’s the matter? 你好像很着急，怎么了？
b: my computer isn’t working and i have got an important contract to type. 我的电脑坏了，可我还有一份重要合同要打出来。
a: why don’t you call the computer company? 你为什么不给计算机公司打个电话？
b: i did, but they said the company was short of hands and couldn’t send any man today. 我打了，可他们说人手不够，今天不能派人来。
a: what should i do? 我该怎么办呢？
22.be supposed to 认为应该，必须；认为可以
此语用被动语态表示“被许多人相信”，如：the castle is supposed to be haunted.（人们都说那座城堡闹鬼。）此语在口语中表示“认为可以做某事”，如：none of us girls is supposed to smoke.（我们女孩子都不吸烟。）此语中的supposed是动词的过去式，supposed作为形容词，意指“假定的，被信以为真的，想象中的”。
a: the train was supposed to get to beijing at eight o’clock. 火车该八点钟到北京。
b: eight o’clock? it’s already eight-thirty. 八点？现在都八点半了。
a: what if he didn’t see us? 要是他没看见我们怎么办？
b: he would take a taxi, i think. 他会打出租车的。
a: maybe the train is late. 不会是火车晚点了吧。
b: it is impossible. i have heard the broadcast. 不可能。我已听见广播了。
23.be too quick on the trigger 操之过急，行动过于仓促
trigger指枪的“扳机，触发器”。该习语直译为“过早地扣动扳机”，引申为“行动过于仓促，操之过急”。
a: you shouldn’t have had bob do that job. he is still a green hand. 你不该让鲍勃做那项工作，他毕竟还是一个新手。
b: but he needs to be given a chance. 但是他也需要机会呀！
a: you should not have been too quick on the trigger. 可你不该太性急呀！
24.bear down 加倍努力
该习语本身就有“竭尽全力、加紧努力”的意思。例如：you will bear down if you expect to pass the exam. （你要是指望考试及格的话，就得加一把劲。）
a: if we can’t finish the work before deadline, we will be fined according to the contract. 如果我们不能在规定的期限内完成工作，根据合同，我们将会被罚款。
b: we are already bearing down to do the work. 我们已经在很努力地工作了。
a: i know. what i mean is that we should improve our efficiency. 我知道。我的意思是我们必须提高效率。
25.beat someone at his own game 将计就计地惩罚某人
习惯用语beat someone at his own game直译为“以某人自己设计的把戏打击某人”，与汉语的“将计就计”近似。
a: you seem to be worried about something. 你看上去很担心。
b: yeah. i don’t know how to deal with that smart businessman. 是呀。我不知道该怎么对付那个狡猾的商人。
a: don’t worry. let’s beat him at his own game. 别担心，我们可以将计就计。
b: a good idea. 好主意。