They will wait at the entrance to welcome their parents(划线部分to welcome their parents)
问题描述：
They will wait at the entrance to welcome their parents(划线部分to welcome their parents)
答
What will they wait to do at the entrance?
句意：他们将要在入口处等待做什么事?
用what对不定式to do提问.what will they wait at the entrance for?可以吗？或者是why will they wait at the entrance?从意思上好像说得通，但不符合这道题目的要求。这两个句子用来对because引导的原因状语从句提问，而这句话是用不定式to do 来做目的状语，问答不协调。老师给的答案是why ，不过你答案也应该是正确的吧我给你提供一些建议，相信你自己的判断吧。