[Grammar] In what way should I distinguish "may have done" from "might have done"?

[jutfrank]

Re: In what way should I distinguish "may have done" from "might have done"?

deductions in the past
Ali must have travelled. That means I am sure 90percent he travlled.
Ali may have travelled. That means I am sure 70 percent he travlled.
Ali might have travelled. That means I am sure 30 percent he travlled.
It is the British native way which I had been taught a long time ago.

It is certainly not "the British native way". There are so many things wrong with what you've said there that it's hard to know where to start! Only the first of those sentences is a deduction, which is a way to arrive at a logical certainty.

 

[abo.omar]

Re: In what way should I distinguish "may have done" from "might have done"?

It is certainly not "the British native way". There are so many things wrong with what you've said there that it's hard to know where to start! Only the first of those sentences is a deduction, which is a way to arrive at a logical certainty.

yes, I am so sorry.
The second and third ones are possibilities.

 

[Charlie Bernstein]

Re: In what way should I distinguish "may have done" from "might have done"?

deductions in the past
Ali must have travelled. That means I am 90% sure he travelled.
Ali may have travelled. That means I am 70% sure he travelled.
Ali might have travelled. That means I am 30% sure he travelled.
It is the British native way, which I was taught a long time ago.

I'm sure the Brits here will agree.

In American English, He must have traveled can also be a deduction that he did travel. Must can show 100% confidence, depending on context. (You're not necessarily right. But you're completely confident.)

I wonder who computed those percentages.

 

[abo.omar]

Re: In what way should I distinguish "may have done" from "might have done"?

I'm sure the Brits here will agree.

In American English, he must have traveled is a deduction that he did travel. Must shows 100% confidence. (You're not necessarily right. But you're confident.)

I wonder who computed those percentages.

The English authors who want to simplify the rule for the non-native learners.

 

[abo.omar]

Re: In what way should I distinguish "may have done" from "might have done"?

deductions in the past
must have
may have
might have
can't have
possibilities in the past
must have
could have
may have
might have

 

[Charlie Bernstein]

Re: In what way should I distinguish "may have done" from "might have done"?

The English authors who want to simplify the rule for the non-native learners.

Good answer. Thanks!

You might also say tendency. Rule is too rigid for a lot of English language habits.

 

[5jj]

Re: In what way should I distinguish "may have done" from "might have done"?

deductions in the past
must have
may have
might have
can't have

Only must have and can't have suggest present-time logical deductions on the part of the speaker about past situations.

May have and might have are simply the speaker's assertions of past possible actions.

 

[PaulMatthews]

Re: In what way should I distinguish "may have done" from "might have done"?

The English authors who want to simplify the rule for the non-native learners.

That may be so, but it doesn't mean that native speakers agree with it.

For example, not everyone uses both "may" and "might" for past time. Usage depends on dialect.

See my answer at #15 for an explanation.

 

[jutfrank]

Re: In what way should I distinguish "may have done" from "might have done"?

deductions in the past
must have
may have
might have
can't have
possibilities in the past
must have
could have
may have
might have

What's your question? Are you asking us to correct this?

 

[abo.omar]

Re: In what way should I distinguish "may have done" from "might have done"?

What's your question? Are you asking us to correct this?

I just try to re-call them.
They even do not put may have in this modern book.

 

[Charlie Bernstein]

Re: In what way should I distinguish "may have done" from "might have done"?

What's your question? Are you asking us to correct this?

Abo is just showing me the British order of likelihood. (See posts 23 and 24.)

He was responding to my comment that, in terms of likelihood, may and might seem to same to these American ears.