TO OR NOT TO? MODALS VS. REGULAR VERBS EXERCISE 1 (ESL)
level: Beginner/Intermediate (A2/B1)
This exercise mixes two different types of verbs on purpose. True modal verbs (can, must, could, should, will, would) are always followed by the base form — never to. But many ordinary verbs (want, try, hope, decide, know how) work the opposite way and need to before the next verb. The only way to choose correctly is to look at the word right before the blank each time, not apply one rule to the whole exercise. Exercise 1 of 2.
Grammar review
Modal verbs with the infinitive — core meanings
Modal verbs are followed directly by the base form (infinitive without to). Each modal expresses a specific attitude or degree of certainty about an action.
CAN — ability or possibility: “She can speak three languages.”
CAN’T / CANNOT — impossibility or prohibition: “You can’t park here.”
COULD — past ability or polite possibility: “He could run very fast as a child.”
MUST — strong obligation or logical necessity: “You must wear a seatbelt.”
MUSTN’T — prohibition (stronger than can’t): “You mustn’t touch that.”
SHOULD — advice or recommendation: “You should see a doctor.”
SHOULDN’T — advice against: “You shouldn’t eat so much sugar.”
WILL — future prediction or decision: “I will call you later.”
WOULD — hypothetical or polite request: “Would you help me?”
Key structure note: Modal + base verb (no to, no -s, no -ed)
✗ She cans swim. ✓ She can swim.
But not every verb works this way. Many common verbs are followed by to + the base form instead of the bare infinitive:
WANT: “I want to see you tomorrow.”
TRY: “She tried to finish on time.”
HOPE / DECIDE / PLAN / NEED all follow the same pattern.
KNOW HOW: “He doesn’t know how to swim.”
The trick: look at the word right before the blank. If it's a true modal (can, must, could, should, will, would), never use to. If it's an ordinary verb like want or try, you almost always need it.
Modal verbs are followed directly by the base form (infinitive without to). Each modal expresses a specific attitude or degree of certainty about an action.
CAN — ability or possibility: “She can speak three languages.”
CAN’T / CANNOT — impossibility or prohibition: “You can’t park here.”
COULD — past ability or polite possibility: “He could run very fast as a child.”
MUST — strong obligation or logical necessity: “You must wear a seatbelt.”
MUSTN’T — prohibition (stronger than can’t): “You mustn’t touch that.”
SHOULD — advice or recommendation: “You should see a doctor.”
SHOULDN’T — advice against: “You shouldn’t eat so much sugar.”
WILL — future prediction or decision: “I will call you later.”
WOULD — hypothetical or polite request: “Would you help me?”
Key structure note: Modal + base verb (no to, no -s, no -ed)
✗ She cans swim. ✓ She can swim.
But not every verb works this way. Many common verbs are followed by to + the base form instead of the bare infinitive:
WANT: “I want to see you tomorrow.”
TRY: “She tried to finish on time.”
HOPE / DECIDE / PLAN / NEED all follow the same pattern.
KNOW HOW: “He doesn’t know how to swim.”
The trick: look at the word right before the blank. If it's a true modal (can, must, could, should, will, would), never use to. If it's an ordinary verb like want or try, you almost always need it.
Choose the correct option to complete each sentence.
1. I want ________ you tomorrow.
Correct answer: to see — after want, use the infinitive with to — want to see.
2. I can't ________ you tomorrow.
Correct answer: see — after modal verbs like can't, use the base form — can't see.
3. You must ________ hard.
Correct answer: study — after must, use the base form — must study.
4. Heather tried ________, but she was too tired.
Correct answer: to study — after tried, use the infinitive with to — tried to study.
5. I can't ________ you.
Correct answer: hear — after modal can't, use the base form — can't hear.
6. He wants ________ what she is saying.
Correct answer: to hear — after wants, use the infinitive with to — wants to hear.
7. I want ________ a doctor.
Correct answer: to be — after want, use the infinitive with to — want to be.
8. I must ________ sick. I have a fever.
Correct answer: be — after modal must, use the base form — must be.
9. I couldn't ________ to the movies with Fiona.
Correct answer: go — after modal couldn't, use the base form — couldn't go.
10. Alex does not know how ________.
Correct answer: to drive — after how in a question, use the infinitive with to — how to drive.
CHECK OUT OUR OTHER MODAL VERB EXERCISES:
To or not to? Modals vs. regular verbs 2 (B)
Mixed modals 1 (can, should, must) (I)
Mixed modals 2 (can, should, must) (I)
Mixed modals 3 (can, should, must) (I)
Modals of speculation 1 (I)
Past modals 1 (I)
Modals (couldn’t / might not) (I)
To or not to? Modals vs. regular verbs 2 (B)
Mixed modals 1 (can, should, must) (I)
Mixed modals 2 (can, should, must) (I)
Mixed modals 3 (can, should, must) (I)
Modals of speculation 1 (I)
Past modals 1 (I)
Modals (couldn’t / might not) (I)
