Modal Verbs Practice Worksheet - Fill in the blanks with appropriate modal verbs like may, might, could, can't, and must.

Task: Use a modal verb to complete the sentences.

#### Grammar Recap:
- 100% positive: Must
- 100% negative: Can't
- 50% positive: May, Could, Might
- 50% negative: May not, Might not
- Questions: Could

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Solution:

1. They ________ be away for the weekend but I'm not sure.
- Since there is uncertainty ("but I'm not sure"), use a 50% positive modal verb.
- Answer: They might be away for the weekend but I'm not sure.

2. ________ you open the window, please?
- This is a request or polite question, so use "Could."
- Answer: Could you open the window, please?

3. Nobody is answering. They ________ be out.
- There is some uncertainty here, so use a 50% positive modal verb.
- Answer: Nobody is answering. They might be out.

4. He ________ be French judging by his accent.
- Based on evidence ("judging by his accent"), use a 50% positive modal verb.
- Answer: He could be French judging by his accent.

5. ________ play the piano, please?
- This is a request or polite question, so use "Could."
- Answer: Could play the piano, please?

6. You ________ speak during an exam.
- This is a strict rule or prohibition, so use a 100% negative modal verb.
- Answer: You can't speak during an exam.

7. She's been awake for 24 hours, she ________ tired.
- Given the context ("been awake for 24 hours"), it is highly likely she is tired, so use a 100% positive modal verb.
- Answer: She's been awake for 24 hours, she must be tired.

8. You ________ be right but I'm going back to check.
- There is some doubt ("but I'm going back to check"), so use a 50% positive modal verb.
- Answer: You might be right but I'm going back to check.

9. Lucy ________ go out yet, she hasn't finished her dinner.
- There is a clear reason why Lucy cannot go out (she hasn't finished her dinner), so use a 100% negative modal verb.
- Answer: Lucy can't go out yet, she hasn't finished her dinner.

10. With luck, tomorrow ________ be sunny.
- This expresses a possibility or hope, so use a 50% positive modal verb.
- Answer: With luck, tomorrow might be sunny.

11. My phone won't turn on, it ________ be broken.
- Based on the evidence ("won't turn on"), use a 50% positive modal verb.
- Answer: My phone won't turn on, it could be broken.

12. The exam ________ be easy, you never know.
- There is uncertainty ("you never know"), so use a 50% positive modal verb.
- Answer: The exam might be easy, you never know.

13. ________ you buy me a chocolate bar?
- This is a request or polite question, so use "Could."
- Answer: Could you buy me a chocolate bar?

14. I ________ go to the party tomorrow but I'm not sure yet.
- There is uncertainty ("but I'm not sure yet"), so use a 50% positive modal verb.
- Answer: I might go to the party tomorrow but I'm not sure yet.

15. She knows she ________ be at the bus stop before 5 o'clock.
- This expresses certainty or obligation, so use a 100% positive modal verb.
- Answer: She knows she must be at the bus stop before 5 o'clock.

16. I see some clouds, it ________ rain later.
- This expresses a possibility based on observation, so use a 50% positive modal verb.
- Answer: I see some clouds, it might rain later.

17. We ________ fail, but we have to try!
- This expresses a strong possibility or likelihood, so use a 100% positive modal verb.
- Answer: We must fail, but we have to try!

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Final Answers:

1. might
2. Could
3. might
4. could
5. Could
6. can't
7. must
8. might
9. can't
10. might
11. could
12. might
13. Could
14. might
15. must
16. might
17. must

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Boxed Final Answer:

\boxed{
\begin{aligned}
1. & \text{ might} \\
2. & \text{ Could} \\
3. & \text{ might} \\
4. & \text{ could} \\
5. & \text{ Could} \\
6. & \text{ can't} \\
7. & \text{ must} \\
8. & \text{ might} \\
9. & \text{ can't} \\
10. & \text{ might} \\
11. & \text{ could} \\
12. & \text{ might} \\
13. & \text{ Could} \\
14. & \text{ might} \\
15. & \text{ must} \\
16. & \text{ might} \\
17. & \text{ must} \\
\end{aligned}
}