The boy ________is helping the old man is John's brother用疑问代词填空
问题描述：
The boy ________is helping the old man is John's brother
用疑问代词填空
答
The boy( who )is helping the old man is Jhon's brother .
答
这个是定语从句，先行词在从句中做主语，用that或who。
不懂可以追问。
答
The boy that /who is helping the old man is John's brother
这是一句定语从句,填的是关系词
先行词【boy】在从句中作主语,又指人,所以用【that/who】
答
who