He looks exhausted. He __________ (must / can’t / might) have slept well last night.
👉 Answer: can’t have slept (THIS IS A GUESS)
I didn’t bring an umbrella. I __________ (must/ may/ should) have checked the weather forecast.
👉 Answer: should have checked (THIS IS A REGRET)
She didn’t answer. She __________ (might / must / can’t) have been in a meeting.
👉 Answer: might have been (I DON'T KNOW, BUT I GUESS SO!)