A. Complete the blanks whith a modal of deduction. The context will help to determine the correct modal: (must, may, might, could, can't)

1. The lights are off, and no one's answering the door. They __________ be out of the house. 
2. He __________ be at the office; his car is parked outside.
3. Sarah is very good at mathematics, so this problem ____________ be difficult for her.
4. I heard some strange noises coming from the attic. It ___________ be the wind, but I’m not sure.
5. This package is very heavy. It ___________ contain something fragile.
6. John looks exhausted today. He ___________ have stayed up late last night.
7. The train is always on time, so it ___________ be late today.
8. You __________ want to double-check your answers before submitting the test.
9. They ___________ have left already; the meeting isn't until an hour from now.
10. With those dark clouds, it ____________ start raining soon.

B. The correct past tense modal of deduction should be chosen: (must have, may have, could hace, might have, can't have)

1. The kitchen is a mess. The kids ____ been playing in here.
2. She didn't answer my calls all day. She ____ been busy with something important.
3. The road was wet this morning. It ____ rained last night.
4. I can't find my keys anywhere. I ____ left them at work.
5. He looks so happy today. He ____ received good news.
6. There was no cake left by the time I arrived. It ____ been really delicious.
7. They ____ forgotten about the meeting; they didn’t show up.
8. You ____ seen them at the party yesterday; they were definitely there.
9. The door was open when I got home. Someone ____ been inside.
10. She ____ have known about the surprise; she seemed genuinely shocked.