An advanced course in theoreticalchemistry is the works.

　　87、 keep to oneself

　　I’m amazed that you still haven’t gotten to know your neighbors.

　　88、 kill time 浪费时间

　　Gosh, what can we do to kill the next 10 hours?

　　89、 leave…up to somebody

　　We’ll have to leave the decision up to him.

　　90、 letter of recommendation 推荐信;letter of reference推荐信

　　91、 look on the bright sides of things 看事物的光明面

　　92、 no kidding 不是开玩笑吧

　　93、 on the tip of one’s tongue 就在舌尖

　　A: Are you sure you can’t remember the name of that record?

　　B: It’s just on the tip of my tongue!

　　94、 quitting time 下课时间

　　I’m glad it’s almost quitting time.

　　95、 take it over 重修

　　Don failed physics and had to take it over.

　　96、 than necessary 比应该的要冷

　　The lab was cooler than necessary.

　　97、 That’s easer said than done. 说来容易做来难

　　98、 There is nothing to it. 没什么、很容易

　　I can run this projector. There’s really nothing to it.

　　99、 with flying colors 成功

　　A: How did Ellen do on her American History exam?

　　B: She passed with flying colors.

　　100、 You can bet your life 当然

　　A: Will Prof. Smith come to class on time?

　　B: You can bet your life.