问题
单项选择题
______ that the formation of the sun, the planets, and other stars began with the condensation of an interstellar gas cloud.
A．It is believed
B．To believe
C．To be believed
D．Believed
答案
参考答案：A
解析： 这是一个主语从句后置的句型。因为主语从句过长，故用一个形式主语it代替。It is believed that意为“大家都相信”，相同句式还有it is well known that，意为“众所周知”。