We should check our papers before we hand in them ,________ ________RT,这里应该填shouldn't we 还是didn't we.还有,什么时候填另外一个?
问题描述：
We should check our papers before we hand in them ,________ ________
RT,这里应该填shouldn't we 还是didn't we.还有,什么时候填另外一个?
答
shouldn't we.因为主句中所引用的助词为should,
在句子中没有助动词,系动词,情态动词时就只能借用助动词了,也就是用didn't we的时候.