单选题
_____ is the center "of our planetary system was a difficult concept to grasp in the Middle Ages.无
A、
It is the sun and not the earth
B、
Being the sun and not the earth
C、
The sun and not the earth
D、
That the sun and not the earth
【正确答案】
D
【答案解析】
句意： 太阳而非地球是行星系中心的事在中世纪是很难被人理解的概念。 题干句子缺主语部分， 只能用that-clause主语从句。
提交答案
关闭