Verb forms don't "refer to" other verb forms, so something is wrong with your description of the situation. Maybe you could give an example or two to help us understand your question better. In any case, a modal perfect is neither a present perfect nor a past perfect.
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CalifJimCould is past tense of can
I wonder what that loud sound is. Could/Might it be an airplane?
I wondered what that loud sound was. Could/Might it have been an airplane?
English 1b3Could is past tense of can.In terms of its form, yes. But in terms of usage, note that the "past forms" of modals (would, could, should, might) are frequently borrowed into present (or future) time situations for various reasons, including politeness and uncertainty.
English 1b3Why does your first example refer to th
English 1b3I wonder what that loud sound is. Could/Might it be an airplane?Yes. (Note that "borrowing into the present" is my own way of describing this. I doubt you'll find it explained that way in a formal textboo
1) So this is an example of could being borrowed into the present due to it's being used to express uncertainty?
English 1b3expressing something that is about to happenModality is somewhat beyond tense and time; it's more like attitude. Your examples are not of things about to happen, anyway. They may happen; they may not happen.
English 1b3But sometimes modals do express time, tense, correct?Yes, but often the expression of time is vague or not the main reason for using the modal verb. For example, should gives advice. There's no point in giving advice about a situation that's already occurred in the past. So should can only indicate present time, not past. As I hav
CalifJimSo should can only indicate present time, not past.I assume you are not including the pefect modal tense: should have.