请问May be 和May have been 的区别,它们分别在什么时候用?

问题描述:

请问May be 和May have been 的区别,它们分别在什么时候用?

第一个是对现在或者将来的猜测
第二个则是对过去的猜测.
例如:You may be right.
You may come tomorrow.
He may have come here this morning but he didn't.