Choose the correct modal constructions.

Choose the correct option.

Philip [might fail|might failed|might have failed] that exam, but I don't know that for sure.

Andy and Greta [should have become|should have became|should become] friends in 2019, but they didn't.

Graham [can't have sung|can't has sang|can't have sing] it; he's not a good singer.

They [must were|must have been|must been] on vacation; they're relaxed and tanned.

We [shouldn't have been|should't to be|should have been] rude to the teacher; she's so angry now!