Imagine the following scenario: You were in class, and your professor made a guess and said

Professor: "Climate change may have led the dinosaur to extinction."

After the class, you are about to say this sentence to your colleagues. Would you say

(A) The professor mentioned that climate change may have led the dinosaur to extinction.


(B) The professor mentioned that climate change might led the dinosaur to extinction.


(C) The professor mentions that climate change may have led the dinosaur to extinction.

In fact, my question is essentially that when you want to express someone made a guess about the past event, how can we say it correctly?

By the way, I include (C) as part of possible options because it seems like when people talk about something in the past, they sometimes use the present tense rather than the past tense. Still, as a non-native speaker, I'm not really sure which is correct. I'm quite confused about it.

So, I would like to know which is the correct way to say. Or is neither of them correct by any chance? If so, how can I say it for this? I will appreciate any comment!

  • 1
    Extinct is an adjective, so we have to say that the dinosaurs became extinct. There is some ambiguity about whether to use may or might, but I would say "The professor mentioned that climate change may be the reason that dinosaurs became extinct." Sep 16, 2022 at 12:46
  • What Kate said, or replace "to extinct*" with "to extinction".
    – gotube
    Sep 16, 2022 at 13:47
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    In order to save us effort in answering, please use the "Edit" button on your question to add what you already know about shifting tenses in indirect speech. Also, please tell us what research you've done on your own to answer this question before asking here, and what about it didn't satisfy you
    – gotube
    Sep 16, 2022 at 13:50
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    I think there's a potential nuance of difference in using mentioned rather than the obvious verb said in such contexts. Maybe it's just me, but I think mentioned implies an assertion (regardless of any possible qualifiers such as may / might have) that's known and/or believed by many people, whereas if he simply said that something might be true, it's possible the professor is in fact the only person who ever made or believed that assertion. Sep 16, 2022 at 15:08
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    @gotube Ahh.. I didn't know there's a term until u told me. I just read the grammar tip from Cambridge dictionary and I think I have figured it out and the appropriate response would go to (A) (see dictionary.cambridge.org/grammar/british-grammar/…). (C) is also correct if the speaker is using the time shift to show vividness (see thoughtco.com/tense-shift-verbs-1692461). Is that correct?
    – Eric
    Sep 16, 2022 at 17:15

2 Answers 2


A is correct. B is nearly correct, you'd say "...might have led...". C is incorrect, in context, because the Professor is not mentioning as you speak, nor is it a general truth that the professor always mentions this. You are referring to a past event, so need a past tense for "mention".

You might use "mentions" in the present tense when referring to a book written by the professor. The act of writing preserves the act of "mentioning" and makes it presently true.

When reporting speech you describe the meaning of what was said. The meaning of "may" and "might" are similar enough (in context) that either could be used. Often when reporting speech you use the same phrasing as the original speaker, but this isn't a grammar rule. It would be possible to report what was said in lots of ways "The professor said that the extinction of the dinosaurs could have been caused by climate change." That preserves the meaning, but not the phrasing.

Now, you might (rarely) use the "historical present". This is highly marked. It sounds odd - deliberately - to make a point.

Yeah, so, I'm sitting there, and in comes the Professor, and he starts waffling on as usual. Then suddenly he mentions that that climate change may have led to the extinction of the dinosaurs. Well, you can imagine what happens next....

It is not common, and learners should use this very cautiously, as it can be misunderstood.

  • Thank you for this explanation but when it comes to historical present (see: en.wikipedia.org/wiki/Historical_present), does (C) become correct? That is, we can say (C) to show the vividness, can't we?
    – Eric
    Sep 18, 2022 at 15:06
  • The historical present is highly "marked". In the context given (discussing a lecture with colleagues) the use of the historical present would seem very odd. However if it was part of a longer narrative it might be possible, I'll edit.
    – James K
    Sep 18, 2022 at 16:38

“May” suggests a high degree of probability and "might" is appropriate for past-tense uncertainty and lower probability. Science shows it could have also been from a meter shower and that caused the major climate change. So "may" leans towards greater certainty would be accurate as told.

  • comments invited. Sep 16, 2022 at 15:11
  • I don't accept that “may” suggests a high degree of probability than "might" in any meaningful sense. I'm aware that some people think this, but imho they represent a tiny minority of all Anglophones. So even if those particular people do in fact implement the principle in their own usage, it means nothing if the audience / readership don't recognise any such distinction anyway. Sep 16, 2022 at 15:17
  • @FumbleFingers It seems your opinion is the minority masterclass.com/articles/… Sep 16, 2022 at 19:04
  • Like I said, I don't buy that perspective. I think it primarily originates with grammarians and non-native speakers, who are always keen to find semantic distinctions between alternatives, even though often the difference is either fictitious or is simply a matter of "style / register". Actual native speakers would rarely have any reason to look up a possible semantic distinction between common alternative phrasings, but it's the kind of thing people involved in TEFL are always preoccupied with. Sep 16, 2022 at 19:13
  • I'm a 3rd generation Canadian from English-Scottish background and this is common to my experiences in the last half century. Note the credentials of the authors of that link. FWIW @FumbleFingers . But I agree with you, not everyone implies this rank of uncertainty. Sep 16, 2022 at 20:46

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