问题
选择题
It used to be thought _____ the Earth was flat.
A．as
B．when
C．since
D．that
答案
答案：D
it 为形式主语，此句为 People used to think that the Earth was flat 的被动语态形式。
搜题请搜索小程序“爱下问搜题”
It used to be thought _____ the Earth was flat.
A．as
B．when
C．since
D．that
答案：D
it 为形式主语，此句为 People used to think that the Earth was flat 的被动语态形式。