The boy swimming in the river is my friend Dave.(对swimming in the river 提问)_________boy is _________friend Dave?

问题描述:

The boy swimming in the river is my friend Dave.(对swimming in the river 提问)
_________boy is _________friend Dave?

Which boy is your friend Dave?
swimming in the river 是The boy 的定语 起修饰 限定的作用
(在河里游泳的)男孩
(哪个) 男孩?