This is what I can tell you.
问题描述：
This is what I can tell you.
He did what he could to help his son.
这是什么从句?怎样演变过来的?what 指代什么?
答
一楼english不好还来教人家第一句的what I can tell you明显是表语从句,前面的this is是主语+系动词.原句应是I can tell you this,what就是指代thiswhat he could help his son是作did的宾语,所以应是宾语从句,意思...