may / might用于表推测的用法
表示推测,两者都可用,只是 might 比 may 语气更不确定,表示的可能性更小.
(1) 在句型使用方面：两者均可用于肯定句和否定句,但用于疑问句时,may通常不用于句首,但可用于疑问句的句中（如特殊疑问句等）,而might尽管可以用于疑问句的句首,但不算普通,通常会改用其他句式（如用could等）.如：
He may [might] know the answer.他可能知道答案.
He may [might] not believe you.他可能不会相信你.
And who may [might] she be?那么她会是哪一位呢?
(2) 从时间关系看,对现在或将来情况作推测,后接动词原形；对正在进行的情况作推测,后接 be doing 结构；对过去情况作推测,后接动词完成式.如：
He may [might] tell his wife.他也许会告诉他妻子.
He may [might] be writing a letter.他可能在写信.
She may [might] have read it in the papers.她可能在报上已读到过此事.
(3)“might+完成式”除表示对过去的推测外,还有以下重要用法：
① 表示过去某事可能发生而实际上却并没发生.如：
It was really very dangerous.I might have killed myself.那真的是太危险了,我差点没命了.
A lot of men died who might have been saved．很多人本来可以获救的却死了.
② 表示委婉的批评或责备.如：
You might have made greater progress.你的进步本来可更大一些的.
You might at least have answered my letter.你至少可以回我一封信嘛.