题目内容：

Americans work a lot harder than you do.句子最后为什么有个do?
如题,为什么不直接说Americans work a lot harder than you.而要说Americans work a lot harder than you do.

优质解答

Americans work a lot harder than you do.
这句话有一个连词than ,than连接两边的动词要“平衡”,也就是前后的动词形式一样,这句话前面有一个work,所以后面也要一个动词与之平衡,用万能动词do表示work