Modal Verbs
English Grammar Independent (B2) · 30 lessons
Person A: Do you think it will rain tomorrow? Person B: ______ tomorrow, but I’m not sure.
Correct Answer: It might
- "Might" expresses possibility or uncertainty, which matches Person B's "I'm not sure"—they're saying rain is possible but not definite.
Why the others are wrong:
- It must suggests certainty or obligation ("it definitely will rain"), contradicting "I'm not sure"
- It can means "it's able to" or "it's possible in general," but doesn't express personal uncertainty about tomorrow
- It should implies expectation or obligation ("it ought to rain"), not genuine uncertainty about what will happen
Person A: ______ I see your passport? Person B: Yes, sure.
Why A is correct:
"May" is the polite modal verb for asking permission. It's the standard, formal way to request something from someone.
Why the others are wrong:
- B (Might): Expresses possibility/uncertainty, not a polite request ("Might I see your passport?" is archaic/overly formal)
- C (Should): Means obligation or advice, not permission ("Should I see your passport?" = "Is it a good idea?")
- D (Must): Expresses necessity or demand, which is too forceful and impolite for a request ("Must I see your passport?" = "Do I have to?")
Person A: I don’t have a pen. ______ I borrow yours for a moment? Person B: Of course.
Why A (May) is correct:
"May I borrow...?" is the standard polite way to ask permission. It's the most formal and appropriate choice for requesting something from someone.
Why the others are wrong:
- B (Will) – This is too direct and assumes agreement rather than asking for permission ("Will I borrow?" sounds like stating a plan, not requesting)
- C (Could) – While sometimes used informally, "Could I borrow...?" questions *ability* rather than *permission*, and is less formally polite than "may"
- D (Shall) – This is rarely used for asking permission in modern English; it's outdated and sounds awkward here
Person A: I thought she left her phone in the car. Person B: She can't ______ her phone in the car. It's right here on the table.
A. have left ✓
Person B is contradicting Person A's claim about a past event. "Can't have left" means "couldn't possibly have left" (in the past)—it expresses impossibility about something that already happened.
Why the others are wrong:
- B. had left — Uses past perfect incorrectly; doesn't express the impossibility/contradiction needed here
- C. was left — Passive voice; changes the meaning and doesn't fit the grammar of "can't"
- D. leave — Present tense; doesn't work with "can't" in this context of past events, and doesn't express the impossibility
Person A: The train is leaving soon! Person B: If we hurry, we ______ catch the next train.
Why A is correct:
"Can" means it's *possible* to catch the train if they hurry—this fits the "if" condition perfectly. The sentence structure "If we hurry, we can catch it" expresses possibility.
Why the others are wrong:
- B (must): "Must" means they *have to*, not that it's possible. "We must catch it" sounds like an obligation, not a conditional possibility.
- C (mustn't): This means "must not" or "are forbidden to"—the opposite of what they want to express.
- D (take): Incorrect verb form. "We take the train" doesn't fit the conditional structure; we need a modal verb like "can."
Person A: When I was younger, I used to swim a lot. Person B: Me too, I ______ swim across the lake without stopping.
Why A is correct: "Could" is the past ability form. Person B is matching Person A's timeframe ("when I was younger"), so they need the past tense version of ability.
Why the others are wrong:
- B (can): Present tense—doesn't match the past timeframe ("when I was younger")
- C (should): Means obligation/recommendation, not ability
- D (must): Means necessity/obligation, not ability
Person A: What can we expect if we keep walking? Person B: If we keep walking, we __________ see the lake from the hilltop.
Why A (will) is correct:
Person B is making a confident prediction about a future event—they're certain that if they continue walking to the hilltop, they'll see the lake. "Will" expresses definite future action.
Why the others are wrong:
- B (could) suggests possibility or ability, but Person B sounds certain, not tentative
- C (can) describes ability or possibility in the present, not a future prediction
- D (should) implies obligation or advice ("you ought to"), not a certainty about what will happen
Person A: The lights are on in the house. Person B: If the lights are on, they __________ be at home.
Why "must" is correct:
Person B is making a logical deduction—if the lights are on, that's strong evidence the people are home. "Must" expresses a necessary conclusion based on that evidence.
Why the others are wrong:
- "Want to" doesn't fit grammatically or logically (you don't "want to be at home" based on lights being on)
- "Could" is too weak—it means *maybe* they're home, but the logic here demands a stronger conclusion
- "Would" suggests a conditional or hypothetical situation, not a logical deduction from observable fact
Person A: How can I stay safe while biking? Person B: You __________ wear a helmet while riding a bike for safety.
Should is correct because it expresses a strong recommendation or advisability—helmets are highly recommended for safety, but it's not an absolute legal requirement everywhere.
Might is wrong—it suggests something is possible but uncertain, which downplays the importance of helmet safety.
Could is wrong—it implies capability or possibility, not a recommendation or necessity.
Must is wrong—while helmets are very important, "must" is too strong; it suggests an absolute obligation that may not legally apply everywhere, whereas "should" appropriately conveys practical wisdom.
Person A: Why didn’t she answer her phone? Person B: She __________ been asleep when you called, she didn’t answer.
must have – This is correct because Person B is making a logical deduction or strong conclusion about what probably happened. "Must have" shows that based on the evidence (she didn't answer), Person B is reasonably certain she was asleep.
could have – Wrong because this suggests a mere possibility among many options, not a confident conclusion. It's too weak for Person B's reasoning.
would have – Wrong because this describes a hypothetical condition ("if X happened, then Y would happen"), not an explanation of what actually occurred.
should have – Wrong because this implies obligation or expectation (she was supposed to answer), not a logical explanation for why she didn't.
Person A: I think this should be done today. Person B: No worries, I ______ call her now.
Why D (need) is correct:
"I need to call her now" fits perfectly—it means Person B is saying they will definitely contact her immediately, which directly responds to Person A's request.
Why the others don't work:
- A (must): Grammatically incomplete. "I must call her now" works, but "I must" alone leaves the sentence unfinished—you'd need the infinitive after it.
- B (want): Changes the meaning. "I want to call her now" suggests desire, not commitment, so it doesn't firmly agree with Person A's urgency.
- C (don't): Creates a negative response ("I don't call her now"), which contradicts Person A instead of agreeing to help.
Person A: What’s your work schedule like? Person B: I ______ work from 8 to 5.
Correct answer: "have to"
- "Have to" expresses obligation or requirement, which fits Person B explaining their work schedule as a fixed responsibility.
Why others don't work:
- "Start" — would mean Person B begins work at 8 to 5, which doesn't make sense (8 to 5 is a time range, not a starting point)
- "Finish" — would mean Person B ends work at 8 to 5, which is illogical for the same reason
- "Manage" — doesn't fit the context; it would suggest Person B somehow controls the schedule, rather than describing what it is
Person A: That cough sounds bad. Person B: You __________ see a doctor if that cough doesn't improve.
Correct answer: need to
- "Need to" expresses necessity or obligation—Person B is giving advice that seeing a doctor is necessary if the cough persists.
Why the others are wrong:
- A (have): "You have see a doctor" is grammatically incorrect; needs "to" after "have."
- C (may): "May" suggests possibility ("might be able to"), not the strong recommendation or obligation intended here.
- D (need): "You need see a doctor" is incomplete; "need" requires "to" as an infinitive marker in this context.
Person A: She was fast asleep when I walked in. Person B: She ______ been exhausted.
Correct Answer: must have
Person B is making a logical deduction about a past situation—if she was fast asleep, it's very likely she was exhausted. "Must have" expresses a strong conclusion about something that probably happened in the past.
Why the others are wrong:
- can't have: This means "it's impossible that she was exhausted," which contradicts the logic of the situation.
- must: This is present tense and doesn't fit the past context (she *was* asleep, so we need past tense).
- should have: This suggests regret or an obligation ("she ought to have been exhausted"), not a logical deduction.
Person A: I think you could do better in your studies. Person B: You are right, I really _______ focus more.
Correct answer: ought to
"Ought to" expresses a recommendation or moral obligation based on Person A's suggestion. It fits perfectly after agreeing ("You are right") because B is acknowledging the advice and stating what they should do.
Why the others are wrong:
- Can means "able to" – it doesn't match the context of needing to do better; B already knows they're capable
- Must is too strong and absolute; it suggests an external rule rather than a personal acknowledgment of good advice
- Cannot is negative and contradicts B's agreement with Person A; it would mean B disagrees, not that they accept the suggestion
Person A: How’s your Spanish going? Person B: After taking these lessons, I __________ speak Spanish fluently.
Correct answer: will be able to
- This expresses a future capability that will result from the lessons. "Will be able to" correctly shows that Person B will gain the skill of speaking Spanish fluently as a result of taking lessons.
Why the others are wrong:
- B. take – This is present tense and doesn't make sense in context; it would read "I take speak Spanish," which is grammatically incorrect.
- C. will be – This is incomplete and doesn't convey ability; "I will be speak Spanish" is not proper English.
- D. should be – This suggests obligation or advice rather than a realistic future outcome; it's weaker than the certainty of "will be able to."
Person A: Do you think you'll be fluent after this course? Person B: I ______ be able to speak English more confiidently.
Correct answer: might
- Person B is being realistic about an uncertain future outcome. "Might" expresses possibility—they're not promising fluency, just saying it's *possible* they'll improve.
Why the others are wrong:
- Can: This means ability in the present or general ability, not a future possibility ("I can speak" = current ability)
- Would be: This is conditional and sounds unnatural here; it needs an "if" clause to work properly
- Have: This doesn't fit grammatically or logically in this sentence structure
Person A: The movie was fantastic! Person B: Really? I __________ watch it soon then!
Correct answer: A. have got to
- Person B is expressing a strong obligation or necessity based on Person A's recommendation—they *need* to watch it soon.
- "Have got to" means "must" and shows this strong intention.
Why the others are wrong:
- B. must be – This means "probably is" (speculation), not obligation. It doesn't fit the meaning.
- C. could – This means "might be able to," which is too weak and optional for someone excited to watch based on a recommendation.
- D. would – This is conditional ("if X happened, then I would"), not expressing urgency or necessity.
Person A: The fire alarm went off! Person B: Thankfully we __________ escape the room before it was too late.
A. were able to ✓
This is correct because the sentence describes a completed action in the past. "Were able to" is simple past tense, matching the past-tense context ("The fire alarm went off").
Why the others are wrong:
- B. have been able to — This present perfect suggests an ability that started in the past and continues now, but the sentence needs a simple past action.
- C. will be able to — This is future tense, but the escape already happened.
- D. should have — This implies they *ought to* have done something (judgment/obligation), not that they successfully did it.
Person A: Look at the decoration, it looks nice. Person B: They __________ be preparing for a party!
Why A (must) is correct:
Person B is making a strong logical conclusion based on the evidence (nice decoration). "Must" expresses a deduction—they're confident about what's happening based on what they see.
Why the others are wrong:
- B (can't) – This means "impossible," which contradicts the logic. The decoration actually suggests a party is likely.
- C (will) – This predicts a future action, but Person B is analyzing the present situation, not making a prediction.
- D (could) – This expresses possibility, but it's too weak. Person B sounds more certain than "maybe they could be."
You __________ gotten up so early; the meeting was postponed.
Correct answer: needn't have
This means you didn't need to get up early because the meeting was postponed anyway—it was unnecessary. "Needn't have" expresses that a past action wasn't required.
Why the others are wrong:
- didn't have to: This is close in meaning, but "didn't have to" suggests you had no obligation (a neutral fact), while "needn't have" emphasizes the action was wasteful or pointless in hindsight. The context here blames the unnecessary action.
- must have: This means something definitely happened in the past (deduction), not about necessity. It doesn't fit the meaning.
- should have: This suggests you ought to have done it (advice/regret), but the sentence says the meeting was postponed, so getting up early wasn't advisable.
Person A: What are the rules during the exam? Person B: You __________ talk during the examination.
Correct answer: must not
"Must not" expresses a strict rule or prohibition—exactly what you need when stating exam rules. It's the most formal and authoritative way to say something is forbidden.
Why the others are wrong:
- can't: Means inability, not rules (e.g., "I can't reach the top shelf"). It doesn't convey that talking is prohibited.
- shouldn't: Means advice or recommendation, not a firm rule (e.g., "You shouldn't eat too much candy"). It's too weak for exam rules.
- won't: Refers to future refusal or prediction, not a rule (e.g., "I won't help you cheat"). It doesn't establish what's required.
Person A: It's such a nice day. Person B: __________ we go for a walk in the park this afternoon?
Correct answer: Shall
"Shall we go for a walk?" is the standard polite way to make a suggestion or proposal together. "Shall" is specifically used for offering ideas or asking what someone wants to do.
Why the others are wrong:
- Should: Means advice or obligation ("You should exercise"), not a suggestion to do something together
- Can: Asks about ability/permission ("Can you swim?"), not making a proposal
- Might: Suggests possibility ("It might rain"), not inviting someone to join you
Person A: I thought his injury would stop him. Person B: Despite his injury, he __________ run the marathon.
Correct answer: was able to
- Person A thought the injury would stop him, but Person B is saying he succeeded anyway. "Was able to" shows he actually completed the marathon in the past—it describes a specific accomplishment that happened.
Why the others are wrong:
- B (is able to): Present tense doesn't fit; we're talking about something that already happened.
- C (can): Present tense again, and doesn't convey that he actually did it.
- D (could): This shows general ability or possibility, not a specific past achievement. "Could run" means he had the ability, but doesn't confirm he actually ran it.
Person A: What will happen after the surgery? Person B: After the surgery, she __________ walk without assistance.
Correct answer: A. will be able to
- This uses the future modal "will be able to," which correctly expresses a capability that will exist after a future event (the surgery). The structure is grammatically correct.
Why the others are wrong:
- B. can – Present tense; suggests she can walk without assistance now, not after surgery
- C. could – Past or conditional tense; doesn't fit the future scenario described
- D. will able to – Grammatically incorrect; the verb form should be "will be able to," not "will able to"
Person A: What's the best way to stay healthy? Person B: You __________ eat more vegetables for a balanced diet.
A. should ✓
"Should" is the best choice because it gives advice or a recommendation—staying healthy through vegetables is a good idea, not an absolute requirement.
Why the others don't work:
- B. must — Too strong; it means something is absolutely required or mandatory, not just recommended
- C. could — Suggests it's merely possible or optional, not a genuine recommendation
- D. ought — Similar meaning to "should," but "should" is more commonly used in casual advice like this
Person A: Did you visit your grandparents often? Person B: Every summer, we __________ visit them in the countryside.
Why A is correct:
"Would" expresses a repeated past habit or routine action. It fits perfectly here—Person B is describing something they regularly did every summer.
Why the others don't work:
- B (should): Expresses obligation or advice ("you ought to"), not a past habit
- C (must): Means necessity or strong obligation, not a repeated past action
- D (had): This is just past tense and doesn't convey the sense of a repeated routine; "had visit" is also grammatically incorrect
Person A: Why didn't she come to the party? Person B: She said she __________ go to her aunty's house last night.
A. had to ✓
This is correct because "had to" expresses a past obligation or necessity—she didn't come to the party because she was required/obligated to go to her aunty's house instead.
B. should ✗
"Should" suggests advice or recommendation, not a firm obligation. It doesn't clearly explain why she *couldn't* attend.
C. ought to ✗
Similar to "should," this expresses what's advisable or expected, not a compelling reason that prevented her attendance.
D. was able to ✗
This means she had the capability to do something, which doesn't explain why she chose not to come. It's the opposite of what we need—we need a reason that stopped her from coming.
Person A: With her experience, she should be successful. Person B: Yes, she __________ find a job easily.
Why A (can) is correct:
"Can" expresses ability and is the natural choice when agreeing that someone *is able to* do something based on their qualifications. It matches the certainty in Person A's statement about what "should" happen.
Why the others are wrong:
- B (could) - This is the past tense form; it doesn't fit the future context of "finding a job"
- C (may) - This expresses permission, which doesn't make sense here (no one is granting permission to find a job)
- D (might) - This suggests uncertainty or possibility, but Person B is agreeing with Person A's confident prediction, not expressing doubt
Person A: Did your dad read to you often? Person B: Yes, my dad ______ read me amazing stories every night at bedtime.
Why A is correct:
"Would" shows a repeated habit or routine action in the past—your dad read stories every night regularly. This is the perfect modal for describing something that happened repeatedly on a schedule.
Why the others are wrong:
- B (could) = ability/possibility ("was able to"), not a regular habit
- C (should) = obligation/advice ("ought to"), not describing what actually happened
- D (might) = possibility/uncertainty ("perhaps"), but the speaker is certain this happened every night
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