Grammar: Modal verbs (3) past deduction, speculation, criticism, etc.

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* must have (participle) is used to express a certainty that something happened in the past, normally by deduction. For example: "There are shards of glass on the inside, the window must have been broken from the outside!"

* may/might/could have (participle) are used to express deduction about a possibility. For example: "He may have been drinking last night because he looks terrible today!"

* can't/couldn't have (participle) are used to express past impossibility by deducation. For example: "He can't have studied much for the exam because he failed horribly."

* should/shouldn't have are used to express criticism about something in the past, or to express an opinion that something should have been done differently. For example: "I shouldn't have had that last beer, I have a terrible headache today!"

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Complete the following blanks with the correct form of a modal verb + have + the verb in brackets to express deduction or an opinion about the past.

For example:
0. It's impossible that he has already finished. He ____________ (finish) yet! can't have finished

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 dissapeared to, but I suppose I _____________ (leave) them on my desk. It's certainly a possibility.

5. I'm not surprised you failed the job interview, you ____________ (study) more!

6. You ____________ (tell) her that her hair looked bad, she's going to be upset with you all day.

7. There are puddles of water on the pavement, it ____________ (rain). It's the only explanation.

8. You behaved terribly last night, you ____________ (drink) so much!

9. It's midnight already! We ____________ (spend) the last three hours talking!

10. It's hard to say for certain, but the classical music performance last night ____________ (be) the best I've ever heard.

11. There's a mosquito in here, it ____________ (come) in through the window. No doubt about it.

12. The government ____________ (do) something about the financial situation a long time ago.

13. I can't beleive that you won the football match, your team is terrible. You ____________ (have) a lot of luck!

14. This soup is so thick and tastes so nice! They ___________ (put) a lot of cream in it.

15. I know it's too late to say it now, but I ____________ (waste) so much money on silly things last month.

16. You say that it rained all weekend while you were in London? It ____________ (be) very nice for you.

17. He is such a great athlete, he ____________ (train) hard his whole life.

18. She ____________ (eat) so much chocolate if she really wanted to lose weight.


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