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 managementexam.
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 havegotten rid of it years ago.
B: It runs well and I’ve actually been quite attached to it.
