Intermediate modal verbs. 45 questions on possibility, deduction, advice, and the must vs have to distinction.
What this test covers
- Possibility: May, Might, Could
- Logical Deduction: Must, Can't, Might
- Advice & Obligation: Should, Ought To, Had Better
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All 45 questions with answers
Pick an answer for each question to see if you are right, with the explanation. Submit when you are done; you can submit before answering them all.
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Q1The sky is very dark; it ___ rain later, so you should take an umbrella.
Answer: C. might
The context clue 'the sky is very dark' suggests a future possibility. We use 'might' to express that something is possible but not certain. 'Must' would imply a logical certainty that is too strong for weather, while 'can' usually refers to general ability or permission.
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Q2I am certain she is not at home, so she ___ be in the library.
Answer: A. must
The phrase 'I am certain' indicates a strong logical deduction. We use 'must' for conclusions where we feel sure something is true based on evidence. 'Could' is for weak possibility, and 'can' is not used for specific logical deductions in the affirmative.
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Q3He ___ finish the report by Friday, but it is only a possibility; he hasn't started yet.
Answer: C. might
The phrase 'it is only a possibility' points directly to 'might'. We use 'might' for uncertain future events. 'Must' would imply an obligation, and 'should' would imply a duty or expectation, neither of which match the 'guessing' tone of the sentence.
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Q4She ___ come to the party tonight; she said she was feeling ill.
Answer: C. might not
Because she feels ill, there is a possibility she will stay home. 'Might not' expresses this negative possibility. 'Cannot' is too strong (logical impossibility), and 'must not' is usually used for prohibition (not being allowed to do something).
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Q5It ___ be true that he won the lottery; he hasn't worked for years and just bought a mansion.
Answer: C. must
The evidence (not working and buying a mansion) leads to a strong logical deduction. We use 'must' for things we are almost 100% sure are true. 'May' and 'could' are used for weaker possibilities where we have less proof.
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Q6Where is my phone? It ___ be in the car, or perhaps in my bag.
Answer: C. could
The word 'perhaps' shows the speaker is listing possibilities. 'Could' is used to suggest something that is possible but not certain. 'Must' would be wrong because the speaker is clearly unsure.
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Q7Don't be late; the boss ___ be in a bad mood today.
Answer: A. might
The speaker is suggesting a possible situation. 'Might' is used for possibilities. 'Will' would make it a definite fact, which the speaker likely doesn't know for sure, and 'can' describes general ability rather than a specific chance of a mood occurring.
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Q8I'm looking for the manager. I haven't checked yet, but she ___ be in her office right now.
Answer: D. could
The phrase 'I haven't checked yet' indicates the speaker is making a guess. 'Could' is the correct modal for a possibility when there is no firm evidence. 'Must' would require strong evidence to support a logical deduction, which the speaker admits they lack.
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Q9We ___ go to the beach this weekend, but it depends on the weather.
Answer: C. may
The condition 'it depends on the weather' shows that the plan is not certain. 'May' is used to express a possibility in the future. 'Will' would indicate a definite plan, which contradicts the 'depends' clause.
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Q10That ___ be the postman; it's too early for the mail.
Answer: D. cannot
The clue 'it's too early' provides evidence for a negative logical deduction. We use 'cannot' (or can't) when we are certain something is impossible. 'Must' is the opposite—used when we are certain something is true.
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Q11If you don't study, you ___ pass the exam.
Answer: D. might not
If someone doesn't study, passing becomes an uncertain possibility. 'Might not' expresses this potential negative outcome. 'Must not' is used for prohibition (e.g., 'You must not smoke here'), which does not fit the context of exam results.
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Q12I'm not sure which bus to take; this one ___ go to the city center, but I am just guessing.
Answer: C. could
The phrase 'I am just guessing' tells us the speaker lacks certainty. 'Could' is used for making guesses about possibilities. 'Will' and 'is certain to' express high levels of certainty that contradict the speaker's own admission.
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Q13She's very quiet today; she ___ be tired.
Answer: A. might
The speaker observes a behavior ('very quiet') and suggests a reason. 'Might' expresses a possibility or a guess based on that observation. 'Is' would state a fact, while 'can' is for general ability.
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Q14I ___ see you tomorrow, but I have a lot of work to do.
Answer: D. may
The speaker has a lot of work, so meeting is not certain. 'May' is used for future possibilities. 'Must' and 'should' would imply obligation or duty, which doesn't match the context of a potential meeting.
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Q15That ___ be the right answer; the teacher said it was wrong.
Answer: A. cannot
Since the teacher already confirmed it was wrong, it is logically impossible for it to be right. 'Cannot' is the modal used for logical impossibility. 'Must not' is typically used for prohibition or very strong negative deductions, but 'cannot' is the standard for saying something is impossible.
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Q16He has been running for two hours; he ___ be exhausted.
Answer: C. must
Running for two hours is strong evidence. We use 'must' for logical deductions where the evidence leads to a very likely conclusion. 'Might' would sound too uncertain given the intense physical activity described.
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Q17She just ate a full meal; she ___ be hungry.
Answer: B. cannot
Eating a full meal makes hunger logically impossible. We use 'cannot' for negative deductions when we are certain something is not true. 'Must' and 'should' would suggest the opposite of what the logic dictates here.
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Q18They haven't arrived yet; they ___ be stuck in traffic.
Answer: C. might
The speaker doesn't know why they are late, so they are offering a possibility. 'Might' expresses an uncertain guess. 'Can't' would mean it's impossible they are in traffic, which makes no sense in this context.
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Q19The light is on; someone ___ be home.
Answer: A. must
The 'light is on' is the evidence for a logical deduction. We use 'must' when we are quite sure something is true based on what we can see. 'Might' is too weak for such a clear indicator.
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Q20He failed the test; he ___ have studied very hard.
Answer: C. cannot
For logical impossibility in the past, we use 'cannot have' (or 'couldn't have') + past participle. Since he failed, it is impossible that he studied hard. 'Must not' is used for prohibition or deductions, but 'cannot' is the strongest choice for logical impossibility.
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Q21She speaks three languages; she ___ be very intelligent.
Answer: A. must
Speaking three languages is strong evidence of intelligence. We use 'must' to state a logical deduction that we feel confident about. 'Might' would suggest we are very unsure, which doesn't fit the strong evidence provided.
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Q22They are wearing coats; it ___ be cold outside.
Answer: C. must
Seeing people in coats leads to a logical conclusion about the weather. 'Must' is used for these types of deductions based on visible evidence. 'Can't' would imply it is definitely not cold, which contradicts the evidence.
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Q23I don't know where he is; he ___ be at the gym.
Answer: D. might
The phrase 'I don't know' indicates a lack of certainty. 'Might' is used for making a guess or expressing a possibility. 'Must' would mean the speaker is sure, which they have already denied.
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Q24Given her extensive training, she ___ cook very well.
Answer: D. must
Extensive training is evidence that leads us to a logical conclusion. 'Must' is the modal for a strong deduction. While 'should' could suggest expectation, 'must' emphasizes the certainty derived from her training.
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Q25He is always smiling; he ___ be a very happy person.
Answer: C. must
Constant smiling is the basis for a logical deduction. 'Must' expresses the speaker's high level of certainty about this conclusion. 'Can't' would mean the opposite (impossibility).
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Q26Do you know where ___?
Answer: B. he might be
This is an indirect question. In English, when a question is placed inside another phrase (like 'Do you know...'), we use statement word order (Subject + Verb) instead of question word order. Therefore, 'he might be' is correct, while 'might he be' is for direct questions.
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Q27Can you tell me what ___?
Answer: C. he might want
This is an indirect question starting with 'Can you tell me...'. Indirect questions use standard statement word order (Subject + Modal + Verb). 'He might want' follows this rule, whereas 'might he want' uses the inversion reserved for direct questions.
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Q28I wonder why ___.
Answer: C. she might leave
The phrase 'I wonder' introduces an indirect question. Indirect questions do not use inversion (switching the subject and the verb). We must use the normal statement order: 'she might leave'.
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Q29I'm not sure if ___.
Answer: C. he might come
After 'I'm not sure if', we use statement word order because it functions as an indirect question. The correct pattern is Subject ('he') + Modal ('might') + Verb ('come'). 'Might he come' is the word order for a direct question.
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Q30Could you tell me when ___?
Answer: B. they might arrive
This is an indirect question. We avoid question-style inversion when a question is embedded after 'Could you tell me...'. We use the statement order: 'they might arrive'.
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Q31He failed the test; he ___ have studied very little.
Answer: A. must
To make a logical deduction about the past, we use a modal + 'have' + past participle. 'Must have' is used when we are very sure about a past event based on evidence (his failure). 'Can't have' would mean the opposite.
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Q32She looks happy; she ___ have received good news.
Answer: C. must
Looking happy is evidence of a past event. 'Must have' + past participle is used for strong logical deductions about what happened in the past. 'Should have' would imply she was supposed to receive news but perhaps didn't.
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Q33They didn't show up; they ___ have forgotten the date.
Answer: A. might
The speaker is guessing about a past event with uncertainty. 'Might have' + past participle expresses a past possibility. 'Can't have' would mean it's impossible they forgot, which doesn't fit the context of them being missing.
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Q34I can't find my keys; I ___ have left them at the office.
Answer: B. could
Leaving keys at the office is a past possibility. 'Could have' + past participle is used to suggest something that was possible in the past. 'Should have' would mean it was the speaker's duty or a good idea to leave them there.
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Q35He wasn't there; he ___ have known about the meeting.
Answer: B. couldn't
If he wasn't there, it is logically likely that he was unaware. 'Couldn't have' + past participle expresses logical impossibility in the past. 'Must have' would mean he definitely knew, which would make his absence strange.
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Q36You ___ see a doctor if you feel unwell; it's good advice.
Answer: B. should
'Should' is the standard modal verb for giving advice or making recommendations. The sentence even identifies the statement as 'good advice', which is a direct clue to use 'should'.
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Q37You ___ apologize; it's the right thing to do.
Answer: B. ought to
'Ought to' is used for advice and moral obligation, similar to 'should'. The context 'it's the right thing to do' points to a moral recommendation, making 'ought to' the best fit.
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Q38You ___ leave now, or you'll miss the train.
Answer: B. had better
'Had better' is used for strong advice or warnings. It usually implies that there will be a negative consequence (like missing a train) if the person does not follow the advice.
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Q39The train ___ arrive at 5:00; that is the schedule.
Answer: C. should
We use 'should' to express an expectation based on a plan or schedule. It means we expect the train to arrive at that time. 'Must' would be too forceful, as if we are ordering the train to arrive.
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Q40You ___ study harder if you want to pass.
Answer: A. ought to
This is a piece of advice. 'Ought to' is a modal expression used for advice, followed directly by the bare infinitive (e.g., 'ought to study'). 'May' and 'might' suggest possibility, and 'can' suggests ability, which don't fit a recommendation.
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Q41Which sentence is correct?
Answer: D. You'd better go now.
The expression 'had better' (contracted as 'd better) is always followed by the bare infinitive (the base verb without 'to'). Therefore, 'You'd better go' is correct. Adding 'to' as in 'better to go' is a common grammar error.
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Q42Which sentence is correct?
Answer: A. She should call him.
'Should' is a modal verb and is always followed by the bare infinitive (no 'to'). 'Ought' is an exception and always requires 'to' (e.g., 'She ought to call'). Therefore, 'She should call him' is the only grammatically correct choice.
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Q43Which sentence is grammatically correct?
Answer: D. You'd better not be late for the meeting.
The negative of 'had better' is 'had better not' followed by a bare infinitive. 'You'd better not be' is correct. We do not use 'to be' or 'being' in this specific structure.
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Q44Which sentence is grammatically correct?
Answer: C. You ought to follow the instructions carefully.
'Ought' is unique among modals because it must be followed by 'to' + the base form of the verb. 'You ought follow' is missing 'to', and 'ought to following' uses the incorrect -ing form.
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Q45Which sentence represents the correct form of the modal expression?
Answer: D. They should arrive on time, I expect.
Modal verbs like 'should' are followed by the bare infinitive. This means you cannot use 'to' ('should to arrive'), you cannot add -s ('should arrives'), and you cannot use the -ing form ('should arriving'). Only the base form 'arrive' is correct.
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