1. Piece of cake
例句：The assignment I just finished was a piece of cake.
這個例句說的並不是我剛完成的作業是烤一塊蛋糕，而是指作業非常簡單，a piece of cake就是指輕而易舉的事。
2. Cost an arm and a leg
例句：That Louis Vuitton bag costs me an arm and a leg.
如果在LV買個包包要砍下自己的胳膊和腿，那這個社會就太可怕了!其實，在英語中，如果說到某個東西要cost an arm and a leg，它表達的是某個東西非常expensive。
3. Break a leg
在你即將要走進考場對付討厭的微積分考試前，你們班上成績最好的那個同學突然走過來對你說了句「Break a leg!」 「這個傲嬌鬼」，你忍不住在心裡暗暗抱怨，「成績好就可以這樣詛咒別人嗎?」 但其實那個學習好的傲嬌鬼卻並不是在詛咒你，因為在英文中，break a leg 其實是good luck的意思!
4. Hit the books
例句： The final exam is coming, I might need to go to the library and hit the books.什麼?你要去圖書館打書?!就算期末考再可怕也不能把焦慮發洩在書本上啊...如果你正這麼想，那麼你就誤解這個習語的意思了。其實，hit the books 指的是study,所以例句說的意思是：期末考試就要來了，我可能也該去圖書館看看書學習一下了。
5. Let the cat out of the bag
這個世界上怎麼會有人把貓放在袋子裡?親，要是你這麼想就out了!在英語中，let the cat out of the bag means to disclose a secret that was supposed to be kept(爆料出某個秘密).
6.Hit the nail on the head
這個習語的意思是doing or saying something that is precisely right，中文中有表達叫「正中紅心」或「一針見血」，基本和hit the nail on the head是對應的。
7. When pigs fly
大家見過豬在天上飛嗎?從來沒有吧?當然我也沒見過。其實，這個短語說的就是基本不可能發生的事。
例句：
-- Do you think you can ever win the lottery? (你覺得你會中彩票大獎嗎?)
--Yes. When pigs fly. (等豬會飛的時候我就會中獎了)
8. You can't judge a book by its cover
大家曾經有沒有因為一本書的封面好看而買書?小編我就屬於這樣的人。但是在英文中，judge a book by its cover 卻和書沒有太大關係，它的意思是「以貌取人」。
例句："He dresses in plain clothes and drives an old car. Who would know he is the richest man in town?" "You can't judge a book by its cover."
9. Bite off more than you can chew
It means to attempt to take on a task that is too much for you to handle(眼大肚小).
例句：Our boss bit off more than she can chew when she promised the client we'd have the project ready by next week. It requires at least two weeks!
10. Scratch someone's back
撓背脊是件體力活沒錯吧?既然給自己撓背脊都那麼麻煩了，我們為什麼還要幫別人撓?那是因為這樣的話以後自己背癢的時候才會有人幫你撓。所以這個短語的意思就是預支自己對他人的幫忙，以防日後自己不時之需時可以有人情債可收。也就是中文中常說的：投之以桃，報之以李。
例句：I don't mind driving this time, she's scratched my back plenty of times.