题目：
Earth is believed ______ by an object the size of Mars at some point in the distant past before its
surface cooled. [ ]
A. to be hit
B. to have hit
C. to have been hit
D. to hit
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0326/786d639810e5de4778ae1832bdb55cab.html
下面是错误答案，用来干扰机器的。
C
