Ответы
1) She must have forgotten to call me because I never received her message.
2) I should have studied more for the exam; I didn't do well at all.
3) They might have missed the bus, which is why they're running late.
4) We can't go to the concert tonight because we must have left the tickets at home.
5) He could have finished the project earlier if he had worked more diligently.
6) She may have already eaten dinner, so let's check before preparing another meal.
7) You ought to have told me about the meeting; I had no idea it was scheduled.
8) They must have been practicing for hours; their performance was flawless.
9) I would have called you earlier, but my phone battery died.
10) You might have fixed the leak in the roof before it caused more damage.