What time do you except me back,Mum.////////,Say,half an hour

题目

What time do you except me back,Mum.////////,Say,half an hour
A,at.B,before,C,in.D,for,选哪个,理由

答案

in,意思是在半个小时之内.如果是at和before的话,会有给准确时间,例如：half past ten,ten past nine 之类的.