一道高中英语语法题

Question

____is now the northern Sahara Desert fed much of the civilized world 2500 years ago.
A.This B.It C.What D.That

Answer 1

C
what is now the northern Sahara Desert 是句子主语，意思是现在叫北撒哈拉沙漠的地方；全句的意思是这个地方在2500年以前是世界文明的所在。

Answer 2

C.What