He must try to help his sister with her math?为什么try不加s
问题描述:
He must try to help his sister with her math?为什么try不加s
答
must是情态动词 后面加动词原形 所以不加s
He must try to help his sister with her math?为什么try不加s
must是情态动词 后面加动词原形 所以不加s