问题

The great scientist became world-known in the early 1970s,______ he and another scientist made new discoveries about black holes.

A:which
B:where
C:when
D:then

正确答案是：

同类题型

______ we do must be in the interests of the people.

Have you heard me?— I’m sorry, I youto me

, the two ties are the new arrival of thisseason.–Well , I like ______ of them. Do you have anotherone

People read newspapers and magazines in order to keep themselves _________ of what is going on in the world outside.

Charles did what he could _____ the servant, although he himself was in danger.