They waited silently ().A.for the film beginBwhen thefilm began为什么选B?

问题描述:

They waited silently ().A.for the film beginBwhen thefilm began
为什么选B?

如果选A,要改为:
A.for the film 【to】begin
wait for sb to do sth 结构
如:
They are waiting for the library to open.
They are waiting for the bus to come.
所以只能选B,when the film began 是时间状语从句,修饰waited 这个谓语