TOEIC Modal Verbs: Must, Should, Can, May and Will
After a core modal such as must, should, can, may or will, use the base form of the next verb. Then check meaning: must states an obligation, should often gives advice, and may can express permission or possibility. Must not prohibits an action; do not have to removes the obligation. That difference matters in workplace notices.
Form first: modal + base verb
“The assistant must submit the form” is correct regardless of whether the subject is singular or plural. Must does not take -s, and submit does not become submits. If be follows the modal, be stays in its base form: “The form must be submitted.” The participle after be supplies the passive meaning.
Our bank has 283 items with modal in the skill label: 149 easy, 120 medium and 14 hard. The hard share is 4.9%; the easy share is 52.7%. Those are editorial labels, not evidence that modal verbs are universally the easiest grammar topic. Use this as a compact area to review alongside verb forms.
Choose the message, not just the formula
| Modal | Typical workplace use | Example |
|---|---|---|
| must | Requirement; also strong deduction in context | Visitors must wear an ID badge. |
| should | Advice or expectation | You should save a copy. |
| can | Ability or permission | Staff can access the portal remotely. |
| could | Possibility or a polite request | Could you confirm the date? |
| may | Permission or possibility | The delivery may arrive late. |
| might | Possibility | The room might be unavailable. |
| will | Future statement, willingness or commitment | We will send a confirmation. |
| would | Polite request or hypothetical result | Would you review the attachment? |
Several modals may fit a sentence without enough context. “The team ___ finish today” could take may, might, can or will with different meanings. A valid practice question needs a clue that makes its intended answer defensible; do not pretend all other grammatical possibilities are errors.
Must not is not the opposite of must
| Expression | Meaning | Example |
|---|---|---|
| must not | Prohibited | You must not share your password. |
| do not have to | Not required | You do not have to print the receipt. |
| should not | Advice against an action | You should not leave the booking until Friday. |
“You do not have to print the receipt” allows you to print it if you wish. “You must not print it” forbids printing. In a policy question, look for words such as prohibited, optional, compulsory or permitted. Do not reduce all negatives to a single Thai or English gloss.
Have to behaves differently in questions and negatives: “Does she have to attend?” Core must does not need do-support: “Must she attend?” This is one reason to learn have to as its own construction rather than attach every modal rule to it.
Modal passive and modal perfect
| Construction | Purpose | Original example |
|---|---|---|
| modal + be + past participle | Action received by the subject | All invoices must be approved. |
| modal + have + past participle | A judgment about an earlier event | The courier may have left already. |
| modal + have been + past participle | Earlier event, passive | The parcel might have been delivered. |
In “should have checked,” the checking refers to an earlier opportunity, often with regret or criticism. In “must have checked,” the speaker usually draws a strong inference. Neither phrase automatically tells you that an instruction is being given now.
Read passive voice for the actor/recipient distinction. An opening like “Should you need help” is another use: a formal condition explained in TOEIC conditionals.
Six modal-verb exercises
- The clerk must ___ each entry. (A checks / B checked / C checking / D check)
- The receipts should ___ retained. (A be / B are / C been / D being)
- Password sharing is prohibited. Staff ___ share passwords. (A must not / B do not have to / C might / D can)
- Printing is optional. You ___ print the receipt. (A must / B do not have to / C must not / D cannot)
- The courier may have ___ before we arrived. (A leave / B leaves / C left / D leaving)
- Could you ___ the attachment? (A opened / B opening / C opens / D open)
Answers and a policy-reading drill
- D. A core modal is followed by the base check.
- A. Modal passive uses should be retained.
- A. Prohibited explicitly means must not, not merely unnecessary.
- B. Optional removes the requirement; it does not prohibit printing.
- C. Modal + have requires a past participle: left.
- D. A polite modal question still uses the base open.
Take one workplace notice and mark each action as required, prohibited, optional or recommended. Then rewrite the notice using a suitable modal. This makes you check the force of the message rather than only the verb ending.
Grammar reference: British Council modal verbs. Contrast infinitive and -ing controllers in the gerund guide.
Sources and counting method
The figures come from all 16,214 active, original eng-test.com questions fetched on 27 September 2026. Topic counts use skill labels or exact context tags; groups can overlap. Difficulty means an editorial label, not a measured learner error rate or the difficulty of an official TOEIC paper. Matches /modal/i in tested_skill_en; some items primarily test the verb following a modal rather than choice between modals.
Download the aggregate counts and matching rules. No learner records are included. The exercises in this guide are newly written teaching examples, not official ETS questions. For the wider picture, see our Reading bank analysis.
Frequently asked questions
Should I add -s to the verb after must with he or she?
- No. Use the base form after a core modal: she must submit, not she must submits.
Do must not and do not have to mean the same thing?
- No. Must not prohibits an action. Do not have to means it is not required, although it may still be allowed.
What follows a modal when the sentence is passive?
- Use be + past participle after the modal: must be approved or should be retained.
Does may have left refer to a possible past event?
- Yes. May + have + past participle expresses a possibility about an earlier event. It is different from may leave, which can concern a present or future possibility.