题目内容
【题目】Has it been announced ______?
A.when are the planes to take off
B.that are the planes to take off
C.where are the planes to take off
D.when the planes are to take off
【答案】D
【解析】句意: 飞机什么时候起飞已经宣布了吗?此处是when引导的主语从句,故选D
练习册系列答案
相关题目