a many 和 many a 的用法?

问题描述:

a many 和 many a 的用法?

many a +可数名词单数= many +可数名词复数
例如many a book=many books many a box=many boxes .我老师是这样说

a many 没有这种用法
和 many a =many 但是后面谓语动词用单数