根据句子含义填上所缺单词

问题描述:

根据句子含义填上所缺单词
The boys who____playing football are the Class 3 student.

The boys who (are)playing football are the Class 3 student.
那些正在踢足球的男孩们是三班的学生.
定语从句,who are playing football 修饰 the boys
主语boys为复数,用are.
可以将此句分成两个句子,就可以看出来了:
The boys are playing football;
The boys are the Class 3 student.