11, allergic to 对|……过敏

　　Oh man! Something in this room is making my eyes itch. I must be allergic to something。

　　12, at sb’s service 愿为某人服务

　　I am at your service at any time。

　　13, around the clock 24小时不停

　　Martha studied around the clock for management exam。

　　14, as far as I know 就我所知

　　15，at home with 对…。。很熟悉

　　She is at home with problems like this。

　　16, back out

　　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。

　　17, be cut out for 天生适合

　　I’m not cut out to be a hero。

　　18, be absorbed in

　　She has been absorbed in a horror fiction. I can’t tear her away。

　　19, be addicted to 对……上瘾

　　She has been addicted to drugs for years。

　　20，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。