___ will the train leave?____ five minutes.

问题描述:

___ will the train leave?____ five minutes.
A. How soon...After B. How soon...In C. When...In D. How long...After
答案是C,但B为何不可?

when问是时间点.当然说in five minutes.5分钟之后的那个点
how soon是问时间段(要多久),当然回答five minutes(要5分钟)