In English, we use modal auxiliary verbs to express ideas such as possibility, ability, obligation and compulsion. It is often possible to use the same auxiliary to express different ideas. For example, we can use ‘can’ to talk about ability and possibility.
Test your understanding of modal auxiliary verbs with this grammar exercise.
Complete the following sentences using appropriate modal auxiliary verbs. The idea that you should express is indicated in the brackets.
1. I ……………… be there before 8 o’clock. (compulsion)
2. ………………….. you lend me a few dollars? (polite request)
3. You …………………. not have done this to me. (criticism)
4. She ………………. be driving now. (probability)
5. It …………………. rain in the evening. (weak possibility)
6. You ………………… not have waited for them. (lack of necessity)
7. ………………. I wait any longer? (necessity)
8. You ………………… to follow traffic rules. (obligation)
9. ………………. I turn the heating on? (necessity)
10. You ……………….. have helped me. Why did you just sit and watch? (criticism)
Answers
1. I must be there before 8 o’clock. (compulsion)
2. Would / Could you lend me a few dollars? (polite request)
3. You should not have done this to me. (criticism)
4. She must be driving now. (probability)
5. It might rain in the evening. (weak possibility)
6. You need not have waited for them. (lack of necessity)
7. Need I wait any longer? (necessity)
8. You ought to follow traffic rules. (obligation)
9. Should / Need I turn the heating on? (necessity)
10. You could / should have helped me. Why did you just sit and watch? (criticism)
