Mr.Jones and his wife (are) looking at them 和Sometimes he and his wife watch televsion.区别:

问题描述:

Mr.Jones and his wife (are) looking at them 和Sometimes he and his wife watch televsion.区别:
Mr.Jones and his wife are looking at them 和Sometimes he and his wife watch televsion区别:为什么前面一句看要用系动词are,后一句却不用,但是我是一个人在家自学,所以对我来说理解起来比较困难!

前面一句表示的是现在进行时,用 be doing something
后面一句表达的是一般情况,用动词原形