1) 退出

　　A： Wasn’t Bert supposed to sing tonight?

　　B： Yes but he backed out at last minute

　　2)不履行

　　She finally backed out of her promise.

　　2、 be cut out for 天生适合

　　I‘m not cut out to be a hero.

　　3、 be absorbed in 全神贯注于, 专心致志于

　　She has been absorbed in a horror fiction. I can‘t tear her away.

　　4、 be addicted to 对……上瘾

　　She has been addicted to drugs for years.

　　5、be attached to 对……有感情

　　A： I‘m amazed that you are still driving that old car of yours. I thought you would have gotten rid of it years ago.

　　B： It runs well and I‘ve actually been quite attached to it.

　　6、 back up

　　1) 累积

　　The subway is running behind schedule and traffic is backed up for blocks.

　　I don‘t know if we’ll make the 6：30 show.

　　2) I‘ll back it up.复制，(文件等的)备份

　　7、 be bound for 到……地方

　　The bus is bound for New England.

　　8、 be (feel) myself 找到自我

　　I’m feeling myself again.

　　9、 be burned up 生气

　　She was really burned up at the news.

　　10、 be hard up for 缺少某事物, 需要某事物

　　I‘m hard up for clothes，but I have a lot of books.

　　11、 be head and shoulders above 好许多

　　In calculus， Joe is head and shoulders above his classmates.

　　12、be in the dark 蒙在鼓里

　　A： Do you have any idea what his notice is about?

　　B： I’m as in the dark as you are.

　　13、be stuck 卡住了

　　I can‘t get this window open. It’s stuck.

　　14、 bite off more than one can chew. 贪多嚼不烂

　　A： I hear you‘re taking an advanced physics course this semester.

　　B： I think I‘ve bitten off more than I can chew.

　　15、 break new ground 有了新的突破

　　His architectural design broke new ground in the field.