I don't know when I can post the letter.改为同义句I don't know ___ ___ ___the letter.
问题描述:
I don't know when I can post the letter.改为同义句I don't know ___ ___ ___the letter.
请问这是什么句型?为什么这么填?
答
when to post
这是疑问词+to do sth的省略疑问句形式
I don't know what to do next=I don't know what I will do next