when _____the film ____(begin?it began half an hour ago

问题描述:

when _____the film ____(begin?it began half an hour ago
,用所给词适当形式填空,还要说为什么那样选择.

did begin
因为根据回答可以看出句子是一般过去时,又因为begin是实意动词,所以变一般疑问句是借助于助动词did
我是英语专业的,