What time do you expect me back Mum? -- Say half an hour.A. atB. beforeC. inD. for

问题补充：

-- What time do you expect me back, Mum?

-- Say, half an hour.

A. at

B. before

C. in

D. for

答案：

A. at

B. before

(答案→)C. in

D. for

解析：指望我什么时间回来，半个小时之后意思较符合，in表示在什么时间之后的含义，故本题选C。