Modals of Obligation (Must, Have to, Should) – English Grammar Exercises for A2
You and your friends are trying to decide the best way to get to the airport. Read the conversations carefully and choose the best option (A, B, C, or D) to complete each suggestion or statement.
1 “We want to save money for the trip, so I think we ______ take the subway instead of a taxi.”
(A) have to
(B) must to
(C) should
(D) should to
2 “There is a lot of traffic in the city right now. We ______ take a taxi because we might be late.”
(A) shouldn’t
(B) don’t have to
(C) mustn’t
(D) haven’t to
3 “Friend: I have two very heavy bags. ______ I book a private car?”
(A) Do I have to
(B) Should I
(C) Must I to
(D) Have I
4 “The subway is very cheap, but we ______ carry our bags up the stairs. That might be difficult.”
(A) should
(B) have to
(C) must to
(D) has to
5 “Our hotel offers a free shuttle bus to the airport, so we ______ pay for a ride at all!”
(A) mustn’t
(B) shouldn’t
(C) don’t have to
(D) haven’t to
6 “If we want the fastest and most relaxing route, we ______ take the airport express train.”
(A) must to
(B) should
(C) have to
(D) should to
7 “Friend: ______ leave the hotel now, or wait another 15 minutes?” – “Let’s leave now.”
(A) Do we have to
(B) Must we to
(C) Should we
(D) Are we should
8 “A taxi is much more comfortable, but it is very expensive. We ______ save our money for food.”
(A) should
(B) should to
(C) have to
(D) must to
9 “Hurry up! The train schedule says it leaves at exactly 4:00 PM. We ______ run to catch it!”
(A) should
(B) must to
(C) have to
(D) should to
10 “I think you ______ put your heavy bag on the empty seat. Put it on the floor so someone else can sit down.”
(A) don’t have to
(B) mustn’t
(C) shouldn’t
(D) haven’t to
11 “Mark says we ______ rent a car, but I think the subway is much easier for a large group.”
(A) have to
(B) should
(C) must to
(D) has to
12 “Look at the sign! You ______ eat or drink on the subway train. The fine is $50!”
(A) don’t have to
(B) shouldn’t
(C) mustn’t
(D) haven’t to
13 “To get to the airport quickly, you ______ get off at Central Station and switch to the green line.”
(A) should
(B) must to
(C) have to
(D) should to
14 “______ take a taxi? The subway station is only a 5-minute walk from here, and the weather is nice.”
(A) Should we to
(B) Must we to
(C) Are we have to
(D) Do we have to
15 “It is raining very heavily outside. You ______ walk to the bus stop in this terrible weather.”
(A) shouldn’t
(B) don’t have to
(C) mustn’t
(D) aren’t have to
16 “We ______ tip the taxi driver in this city, but it is a nice thing to do if the service is good.”
(A) mustn’t
(B) shouldn’t
(C) don’t have to
(D) aren’t have to
17 “The subway is closed today for repairs. We have no choice, so we ______ take the bus.”
(A) should
(B) have to
(C) must to
(D) has to
18 “Oh no, I left my passport on the table! I ______ go back to the hotel room right now!”
(A) have to
(B) should
(C) must
(D) must to
19 “If you are feeling tired, we ______ just share a taxi. It is more expensive, but you can rest.”
(A) should to
(B) have to
(C) must
(D) should
20 “Okay, everyone agrees. We ______ take the subway to save $30 on this trip!”
(A) have to
(B) must to
(C) should
(D) should to
ANSWER KEY & EXPLANATIONS
1 Key: (C) should
Explanation: – Why it’s correct: “Should” is the perfect modal to express a good idea or a subjective suggestion (“I think we should…”).
- Meaning Trap (A): “Have to” means an external rule forces you to take the subway, which is not true here.
- Common Mistake (B): “Must to” is always grammatically incorrect.
- Structural Error (D): Never put “to” after “should”.
2 Key: (A) shouldn’t
Explanation: – Why it’s correct: Advising against a taxi because of a negative consequence (traffic/being late).
- Meaning Trap (B): “Don’t have to” means “you are not forced to,” which doesn’t capture the warning that a taxi is a bad idea.
- Meaning Trap (C): “Mustn’t” means a taxi is strictly illegal/forbidden, which is too strong.
- Structural Error (D): “Haven’t to” is invalid.
3 Key: (B) Should I
Explanation: – Why it’s correct: We use “Should I…?” to ask for someone’s opinion or advice.
- Meaning Trap (A): “Do I have to” asks if there is a strict rule forcing you to book a car.
- Common Mistake (C): “Must I to” adds an illegal “to”.
- Structural Error (D): “Have I” requires “to” (Have I to) and is still less natural than “Do I have to” for obligations.
4 Key: (B) have to
Explanation: – Why it’s correct: The physical reality of the subway station (having stairs) forces you to carry your bags. It is an unavoidable circumstance.
- Meaning Trap (A): “Should” means it’s a good idea to carry bags, which doesn’t fit the complaint.
- Common Mistake (C): “Must to”.
- Structural Error (D): “Has to” is wrong for “we”.
5 Key: (C) don’t have to
Explanation: – Why it’s correct: The free shuttle means it is not necessary to pay. There is zero obligation.
- Meaning Trap (A): “Mustn’t” means you are forbidden from paying.
- Meaning Trap (B): “Shouldn’t” is advice, not a statement of fact about a free service.
- Structural Error (D): “Haven’t to”.
6 Key: (B) should
Explanation: – Why it’s correct: Recommending the best option based on a condition (“If we want the fastest route…”).
- Common Mistake (A): “Must to”.
- Meaning Trap (C): “Have to” sounds like a strict command.
- Structural Error (D): “Should to”.
7 Key: (C) Should we
Explanation: – Why it’s correct: Asking the group for a collective decision/opinion.
- Meaning Trap (A): “Do we have to” asks if there is a rule forcing them to leave.
- Common Mistake (B): “Must we to”.
- Structural Error (D): Never combine “are” and “should”.
8 Key: (A) should
Explanation: – Why it’s correct: Giving a personal opinion about managing the budget.
- Structural Error (B): “Should to”.
- Meaning Trap (C): “Have to” makes it a strict rule rather than a smart choice.
- Common Mistake (D): “Must to”.
9 Key: (C) have to
Explanation: – Why it’s correct: A train schedule is a strict external clock. If you don’t run, you miss it. You are forced by the circumstance.
- Meaning Trap (A): “Should” is too weak for catching a train leaving right now.
- Common Mistake (B): “Must to”.
- Structural Error (D): “Should to”.
10 Key: (C) shouldn’t
Explanation: – Why it’s correct: Giving polite advice on social etiquette (it’s rude to put bags on seats).
- Meaning Trap (A): “Don’t have to” implies they can if they want to.
- Meaning Trap (B): “Mustn’t” could work if it’s a strict train law, but “I think you shouldn’t” makes it a piece of friendly advice.
- Structural Error (D): “Haven’t to”.
11 Key: (B) should
Explanation: – Why it’s correct: Reporting Mark’s suggestion/idea.
- Meaning Trap (A): “Have to” would mean Mark is stating a rule.
- Common Mistake (C): “Must to”.
- Structural Error (D): “Has to” is singular.
12 Key: (C) mustn’t
Explanation: – Why it’s correct: “Look at the sign!” and “The fine is $50!” clearly indicate a strict legal prohibition.
- Meaning Trap (A): “Don’t have to” means it’s optional.
- Meaning Trap (B): “Shouldn’t” is too weak for a $50 fine.
- Structural Error (D): “Haven’t to”.
13 Key: (A) should
Explanation: – Why it’s correct: Giving navigational advice. It is the smartest way to go.
- Common Mistake (B): “Must to”.
- Meaning Trap (C): “Have to” implies there are no other trains in the world you could take.
- Structural Error (D): “Should to”.
14 Key: (D) Do we have to
Explanation: – Why it’s correct: The speaker is challenging the necessity of a taxi since the subway is so close. (“Is it really necessary to take a taxi?”).
- Structural Error (A): “Should we to”.
- Common Mistake (B): “Must we to”.
- Structural Error (C): “Are we have to”.
15 Key: (A) shouldn’t
Explanation: – Why it’s correct: Advising against a bad idea (walking in the rain).
- Meaning Trap (B): “Don’t have to” doesn’t capture the warning aspect.
- Meaning Trap (C): “Mustn’t” is too bossy/strict for weather advice.
- Structural Error (D): “Aren’t have to”.
16 Key: (C) don’t have to
Explanation: – Why it’s correct: Tipping is optional. There is no strict rule requiring it.
- Meaning Trap (A): “Mustn’t” means it is illegal to tip a driver!
- Meaning Trap (B): “Shouldn’t” means tipping is a bad idea.
- Structural Error (D): “Aren’t have to”.
17 Key: (B) have to
Explanation: – Why it’s correct: “We have no choice.” An external event (subway closure) forces this action.
- Meaning Trap (A): “Should” implies there are other options to choose from.
- Common Mistake (C): “Must to”.
- Structural Error (D): “Has to” is singular.
18 Key: (C) must
Explanation: – Why it’s correct: A sudden realization of an emergency creates a strong internal obligation. (“I must go back!”).
- Meaning Trap (A): “Have to” works, but “must” is often more natural for sudden, panic-driven internal feelings. However, between the given options, (C) is grammatically flawless while (D) is wrong.
- Meaning Trap (B): “Should” is too weak for a forgotten passport!
- Common Mistake (D): “Must to”.
19 Key: (D) should
Explanation: – Why it’s correct: Offering a kind, flexible suggestion to a tired friend.
- Structural Error (A): “Should to”.
- Meaning Trap (B): “Have to” is too strict.
- Meaning Trap (C): “Must” is too commanding.
20 Key: (C) should
Explanation: – Why it’s correct: Concluding the group’s opinion on the best, most logical action.
- Meaning Trap (A): “Have to” ignores that this was a group choice, not a strict rule.
- Common Mistake (B): “Must to”.
- Structural Error (D): “Should to”.
GRAMMAR POINTS TO REMEMBER
- Should (Suggestions & Opinions):
- We use Should when we want to say that something is a good idea, a smart choice, or the best option. It is a “soft” modal.
- When friends are planning a trip and weighing their options, they use “should” to express their opinions without forcing anyone.
- Example: “We should take the subway to save money.” (It’s my advice, not a law).
- Should I / Should we…? (Asking for input):
- This is the standard way to ask a group for their opinion on a plan.
- Example: “Should we wait for the bus?”
- Have to (The Circumstance Dictates):
- We use Have to when an external factor—like a train schedule, broken rails, or heavy bags—forces you to do something. You don’t have a choice.
- Example: “The subway is closed. We have to take a taxi.”
- The Grammar Rules:
- Rule 1: NEVER put “to” after “should” or “must”.
- Rule 2: NEVER add an “s” to “should” or “must”.
- Rule 3: Treat “have to” like a normal verb. Make questions with Do/Does (e.g., Do we have to go?).