thai is only one of the students who knows the truth?为什么不能用 that knowsThat is the only one of the students who knows the truth 不是说前面是the only 时必须用that 为什么还要用who
问题描述：
thai is only one of the students who knows the truth?为什么不能用 that knows
That is the only one of the students who knows the truth 不是说前面是the only 时必须用that 为什么还要用who
答
that虽然也可以指代人,但是前面的宾语很明确的是一个人,从句用who最合适.