was 和 is 的用法

问题描述:

was 和 is 的用法
was 后面可以接什么.(过去式?原形?)
is 后面可以接什么.(过去式?原形?)

可以接动词ing形式,名词,形容词,副词.He was/is doing homework.He was/is a student.He is friendly.He was/is there.接过去分词表被动He was beaten by his brother.至于原型,接动词是不会出现这种情况的...