问题

14．This doubt had been in my mind for some time, but the research still went on____some reasons

A:to
B:about
C:for
D:In

正确答案是：

同类题型

The disappearance of dinosaurs is not necessarily caused by astronomical incidents. But _________explanations are hard to find.

It was midnight_________ I met Jane yesterday

149 We won’t have _____ without your help

I have a brother and________.

The 15:30 train to Sheffield has been called off _______ situations beyond our control.