问题
选择题
_________ people were watching the sky, the alien got out of the UFO.
A．If
B．When
C．Because
D．While
答案
答案：D
while引导的时间状语从句常用进行时态.
搜题请搜索小程序“爱下问搜题”
_________ people were watching the sky, the alien got out of the UFO.
A．If
B．When
C．Because
D．While
答案：D
while引导的时间状语从句常用进行时态.