who is that boy引导的定语从句

1.Who is that boy standing outside the window?站在窗外的男孩是谁

2.Who is that boy's father?这小孩的父亲是谁

3.Who is that boy in red sweater?那位穿红色毛衣的男孩是谁

4.I want to know who that boy is。我想知道那个男孩是谁. 

5.Who is that tallest boy?谁是最高的男孩