This grammar exercise tests your ability to use modal auxiliaries correctly.
Fill in the blanks with an appropriate modal auxiliary.
1. They knelt in front of the child who ............................ one day rule their country.
The main verb is in the past tense, so we need an auxiliary referring to the past time in the dependent clause.
2. How many people ...................... get into a telephone booth?
We use 'can' to talk about theoretical possibility.
3. I .............................. not do this if I did not have to.
If the verb in the if-clause is in the simple past tense, we use 'would + infinitive' in the main clause.
4. If you stopped talking, I ......................... get some work done.
5. ................................. a visa for Malaysia?
The auxiliary need is followed by an infinitive without to.
6. You ........................... better start saying thank-you.
The correct expression is 'had better'.
7. Let's go for a walk, ............................ we?
After 'let's' we use 'shall we' in question tags.
8. You ............................... work on Sundays.
Need can be used as an auxiliary verb and as a regular verb. When need is an auxiliary, it is followed by an infinitive without to. When need is used as a regular verb, it is followed by an infinitive with to and questions and negatives are made with do.
9. She really ........................... to mend her ways.
Ought is followed by an infinitive with to.
10. She ............................. speak six languages.
We use can to show ability; may indicates possibility.
11. Life ............................... be more interesting when I was a child.
Would cannot be used to talk about habitual states in the past. Only used to is possible with that meaning.
12. Granny ....................... always bring us nice gifts.
Both 'would' and 'used to' can be used to talk about past habits.
Answers
1. They knelt in front of the child who would one day rule their country.
2. How many people can get into a telephone booth?
3. I would not do this if I did not have to.
4. If you stopped talking, I could / might get some work done.
5. Need I get a visa for Malaysia?
6. You had better start saying thank-you.
7. Let’s go for a walk, shall we?
8. You need not / don’t need to work on Sundays.
9. She really ought to mend her ways.
10. She can speak six languages.
11. Life used to be more interesting when I was a child.
12. Granny would / used to always bring us nice gifts.
