问题

It was after he had read the requirements _______ Mr. Black realized the task was too difficult to be finished.
A:when
B:that
C:which
D:what;
B:that
C:which
D:what;
正确答案是:
同类题型
My funny joke made my grandparents ___ happy.
My teacher’s rich knowledge of science _______ my decision ______ study science[ ]
This word can be used both as a noun ___ as a verb
How old is the man under the tree –I ________ him to be about fifty.
I went to Mount Hua, I was deeply impressedwith its beautiful scenery