Nuances between Modals

[hela]

Dear teachers,

- What is the difference in meaning between all these sentences ? Are they all correct ?

1a) My friend MAY BE ill. = Present; There is a strong possibility ?
b) My friend MIGHT BE ill. = Conditional; There is a weaker possibility ?
c) My friend MIGHT HAVE BEEN ill. = Past, a weak possibility ?

d) She MIGHT not HAVE SEEN him, if he didn’t come up to her. = Past: she saw him.


2a) My friend CAN be ill. = incorrect ? / = Possibility ?
(If correct what's the difference between "CAN BE ill" and "MAY BE ill" ?)

b) My friend COULD BE ill. = Past possibility /
= Conditional: the possibility is stronger than with might ?

c) My friend COULD HAVE BEEN ill. = Past possibility ? difference with b ?

d) She COULD HAVE SEEN him. = past possiblity ?


3a) My friend CAN’T BE ill. = It’s impossible that she is ill.
b) My friend COULDN’T BE ill. = Present: is less certain than with 'can’t'? /
= Past impossibility ?

c) My friend COULDN'T HAVE BEEN ill. = Past impossibility ?
difference with b) ?

d) She couldn’t have seen him = It is impossible that she saw him?


4a) The phone is ringing. It CAN BE Betty. (correct ? expresses possibility ?)
b) The phone is ringing. It MAY BE Betty. (correct ? difference with a) ?)
c) The phone is ringing. It MUST BE Betty. (= certain deduction ?)
d) The phone is ringing. It HAS TO BE Betty. (difference with c) ?)
e) The phone is ringing. It WILL BE Betty. = certain deduction about the
present / prediction ? / difference with c) and d) ?

5a) That will be Roland. I can hear him at the door.

b) “Oh, that will be John. He said he would drop by this afternoon."
(direct speech = certain deduction / prediction)

c) That would be John, Mary thought. He had said that he would probably drop by.
(same thing “present deduction with a high degree of certainty” but in indirect speech ?)

d) That will have been Roland… (what can I add here ?) = (correct ? / possible sentence ?)

- What’s the difference between “would” and “will have been”?)

I know that this is quite long but I would be very grateful if you could answer all of my questions. In different posts if you like.

Best regards,
Hela

[Tdol]

2a)- I wouldn't use 'can' here, use may/could
2b & c- the first is talking about present time, and the second about past time.
4a)- This sound wrong to me
4b- possibility, but far from certain, unlike the rest, which express more certainty.
5c- correct
5d- That will have been Roland- he always phones her at this time. (I've been trying to get through to her)