they是主语,sit in the classroom是谓语, listening to the teacher carefully是现在分词做伴随状语,原句可改为they sit in the classroom,and listen to the teacher carefully at the same time ,但就没有那种同时发生的韵味了,英语中经常用分词,不定式做状语
前面已经有动词sit了,说明这是一个伴随性状态,伴随性动词+ing
给你举个例子:The teacher came into the classroom,handing a book in one of her hands.(通常伴随性动词前面有逗号!!)
有些是不需要的:I like sleeping with the window open(with+sth+形容词)
如果有and连接,那前面什么时态,后面也什么时态
求采纳!谢谢
【俊狼猎英】
listening在这里表示主动 进行。
如果 classroom前面加上and
那么就是连接两个并列成分。这时候 listen 用原型:
students learn their lessons in class.they sit in the classroom (and) listen to the teacher carefully.
listening to the teacher carefully是一个状语从句,伴随性状态
学生坐在教室里学习功课
表示进行时