1.情人眼里出西施。
Beauty is in the eyes of the beholder表示“情人眼里出西施”，其中beholder意为“目睹者”。
例：-It's beyond me that Mary would like to marry James. There is an ugly scar on his face.我真想不到玛丽竟然会想嫁给詹姆斯。他脸上有道难看的疤。
-Beauty is in the eyes of the beholder. Don't be so shallow.情人眼里出西施。你不要这么肤浅。
2.这是有史以来最好的事情。
大家是不是想到了This is the best thing in the history呢?更地道的表达其实是This is the best thing since sliced bread，这里的sliced bread指“切片面包”。
1928年，美国开始销售切片面包机，极大地方便了人们的生活。面包是西方人的大爱，他们常会闭上眼睛，一边咽口水一边想：世界上还有比刚出炉的切片面包更好的东西吗?the best thing since sliced bread就引申为“有史以来最好的事情”。
3.天下没有免费的午餐。
当别人在为一点儿小便宜而高兴时，你就可以告诉他：There is no such thing as a free lunch.
例：-I hear bread is free now in that supermarket. Let's go and get some!我听说那个超市的面包现在免费，咱们快去拿点儿!
-There is no such thing as a free lunch. It's just a trick.天下没有免费的午餐。这只是一个伎俩罢了。
4.你真走运！
大家一定想到了You are very lucky，然而更地道的说法则是：God is shining on you.
例：-You know what, I just won a lottery prize.你知道吗?我刚买彩票中奖了。
-Oh， God is shining on you!天哪，你太幸运了!
5.熟能生巧。
这句话可以说成Practice makes perfect.
例：-My oral English is so poor that I'm nervous when talking with foreigners.我英语口语太差了，所以跟外国人谈话时会紧张。
-Practice makes perfect. Just keep on going.熟能生巧。只需多加练习就好。
鼓励别人要不断地尝试和努力时，美国人也常说If at first you don't succeed, try, try again.
6.这就像是先有鸡还是先有蛋的问题。
这句话用英语表示就是It's a matter of the chicken or the egg或It's a chicken and egg problem.