Writeacher, I downloaded a few details about modals expressing possiblity/probabity but I'm still doubtful about their use. My questions to you are numbers 1-2.
Using modals to talk about the present:
1)Will / won't
We use will and won’t when we are very sure:
•She’ll be at work now.
2)must / might / could / may / can't
•She must be on the bus. (I'm fairly sure this is a good guess)
•She might come soon. (maybe)
•She could be lost. (maybe)
•She may be in the wrong room. (maybe)
•She can’t be at home. (I'm fairly sure this isn't true)
1) Do might/could/may have exactly the same meaning "Maybe"?
2) How would you express the same sentences in the past?
She must have been on the bus.
She might have come soon.
She could have been lost.
She may have been in the wrong room.
She can't have been at home.
Yes, all these are correct:
Using modals to talk about the present:
1)Will / won't
We use will and won’t when we are very sure:
•She’ll be at work now.
2)must / might / could / may / can't
•She must be on the bus. (I'm fairly sure this is a good guess)
•She might come soon. (maybe)
•She could be lost. (maybe)
•She may be in the wrong room. (maybe)
•She can’t be at home. (I'm fairly sure this isn't true)
1) Do might/could/may have exactly the same meaning "Maybe"? Yes, pretty much.
might/may = possibility, perhaps with permission
could = possibility that the person is able to do whatever the verb is
2) How would you express the same sentences in the past? Yes, all the following are correct:
She must have been on the bus.
She might have come soon.
She could have been lost.
She may have been in the wrong room.
She can't have been at home.
1) Yes, "might," "could," and "may" all express possibility or uncertainty in a similar way, which can be translated as "maybe." They all suggest that something is possible but not certain. However, there are slight differences in their usage and level of certainty.
"Might" is often used when there is a lower degree of possibility compared to "could" or "may." For example, if someone says, "He might come later," it implies that there is a smaller chance of him coming than if someone were to say, "He could come later" or "He may come later."
"Could" and "may" are generally used to express higher levels of possibility. For instance, if someone says, "She could be lost," it implies a greater chance of her being lost compared to saying, "She might be lost."
2) To express the same sentences in the past, you need to use the past perfect auxiliary verb "have" in combination with the modal verbs.
So, the sentences would be:
She must have been on the bus.
She might have come soon.
She could have been lost.
She may have been in the wrong room.
She can't have been at home.
These sentences convey the idea that these things were uncertain but possible in the past. The use of "must have," "might have," "could have," "may have," and "can't have" in combination with the past participle of the main verb indicates that these actions or states were possible or not possible in the past, but the speaker is not certain about the actuality.