Задание 3. Use must have + V3, can’t have + V3, might/could have + V3.
1. Bill hasn't arrived for the meeting yet, he (get) stuck in traffic. There's no other possibility.
2. Sally's car is still parked outside her house, she (leave) for work yet because she always goes by car.
3. His phone is out of battery, he (forget) to charge it. I'm certain of it.
4. I'm not sure where my keys have disappeared to, but I suppose I (leave) them on my desk.
5. There are puddles of water on the pavement, it (rain). It's the only explanation.
6. There's a mosquito in here, it (come) in through the window. No doubt about it.
7. This soup is so thick and tastes so nice! They (put) a lot of cream in it.
8. The boss is in a terrible mood. The meeting (be) good.
9. – Helen isn’t here. I guess she (go) home.
– No, she (go) home, her purse is still here.