1 It is called an computer 2 it was bought by my sister 3 it has belonged to our class

问题描述:

1 It is called an computer 2 it was bought by my sister 3 it has belonged to our class
为什么1和2使用be动词,而3使用has

第一个固定句型It is said/reported据说据报道,也可以理解为被动,第二个就是被动,必须用be+v-ed的形式.第三个用的是现在完成时,它的形式是have/has+v-ed,