The key answer of exercise 29.3

1

1. He might have gone shopping.
2. He might be playing tennis.

2

1. She might be watching TV.
2. She might have gone out.

3

1. It might be in the car.
2. You might have left it in the restaurant.

4

1. He might have gone to bed early.
2. He might not have heard the doorbell.
3. He might have been in the shower.

You can use may instead of might in all these sentences.