Modals of Obligation (Must, Have to, Should) – English Grammar Exercises for A2
You are chatting with a friend when you suddenly remember that today is your Mom’s birthday. Read the conversation carefully and choose the best option (A, B, C, or D) to complete your thoughts and responses.
1 “Oh my gosh, today is my mom’s birthday! I ______ call her right now.”
(A) must
(B) should
(C) must to
(D) have
2 “She will be so sad if I forget. I ______ forget to buy a gift on my way home.”
(A) shouldn’t
(B) mustn’t
(C) don’t have to
(D) haven’t to
3 “Friend: You ______ get her some flowers. Mothers always love flowers.”
(A) must to
(B) have to
(C) should
(D) are should
4 “Friend: But you ______ spend a lot of money. A simple card is fine.”
(A) mustn’t
(B) haven’t to
(C) shouldn’t to
(D) don’t have to
5 “No, I love her so much. I ______ find something really special for her.”
(A) must
(B) have to
(C) must to
(D) has to
6 “Wait, the flower shop closes at 6 PM. I ______ leave right now to catch it!”
(A) should
(B) have to
(C) must to
(D) am having to
7 “I ______ remember to write a sweet message inside the card before I give it to her.”
(A) have to
(B) should to
(C) must
(D) musts
8 “I ______ tell my sister about the surprise gift yet. She will ruin it!”
(A) don’t have to
(B) haven’t to
(C) not must
(D) mustn’t
9 “Friend: Maybe you ______ call your sister to ask what Mom wants.”
(A) should
(B) must
(C) have to
(D) should to
10 “That’s a good idea, but I ______ make sure the gift is from my heart.”
(A) has to
(B) must
(C) have
(D) should
11 “Friend: You ______ buy a cake. I know your dad already baked one.”
(A) shouldn’t
(B) mustn’t
(C) don’t have to
(D) haven’t to
12 “I ______ go to the ATM first because the flower shop doesn’t accept credit cards.”
(A) must to
(B) should
(C) must
(D) have to
13 “I haven’t visited her in two weeks. I ______ go see her tonight and give her a hug.”
(A) must
(B) have to
(C) am must
(D) should
14 “I ______ be late for her birthday dinner! I promised I would be there at 7”
(A) don’t have to
(B) mustn’t
(C) shouldn’t to
(D) haven’t to
15 “What kind of flowers ______ I buy for her? Roses or tulips?”
(A) must
(B) have to
(C) should
(D) do I must
16 “I ______ be a good son and make her smile today.”
(A) have to
(B) should to
(C) must to
(D) must
17 “Friend: You ______ rush too much, the dinner isn’t until 7 PM.”
(A) don’t have to
(B) mustn’t
(C) haven’t to
(D) doesn’t have to
18 “I ______ do everything perfectly today. She deserves the best birthday.”
(A) have to
(B) must
(C) musts
(D) should
19 “Friend: You ______ text her right now and say Happy Birthday first.”
(A) must to
(B) have to
(C) should
(D) are should
20 “Yes, I will do that. I ______ remember these dates better in the future!”
(A) have to
(B) should to
(C) must to
(D) must
ANSWER KEY & EXPLANATIONS
1 Key: (A) must
Explanation: – Why it’s correct: “Must” expresses a strong internal obligation or a sudden personal realization. You are forcing yourself to do it out of love.
- Distractor Analysis: (B) is a Meaning Trap (“should” is too weak for this sudden panic). (C) is a Structural Error (never put “to” after “must”). (D) is a Common Mistake (missing “to”).
2 Key: (B) mustn’t
Explanation: – Why it’s correct: “Mustn’t” expresses a strong personal prohibition. You are telling yourself: “It is absolutely necessary that I do not forget.”
- Distractor Analysis: (C) is a Common Mistake (“don’t have to” means it is not necessary, which is the opposite of what you mean here). (A) is a Meaning Trap (“shouldn’t” is too weak). (D) is a Structural Error.
3 Key: (C) should
Explanation: – Why it’s correct: The friend is giving a good suggestion or advice.
- Distractor Analysis: (B) is a Meaning Trap (there is no rule forcing you to buy flowers, so “have to” is wrong). (A) and (D) are Structural Errors.
4 Key: (D) don’t have to
Explanation: – Why it’s correct: “Don’t have to” means there is a lack of obligation (it is not necessary to spend a lot of money, but you can if you want).
- Distractor Analysis: (A) is a Common Mistake (learners often confuse “mustn’t” with “don’t have to.” Mustn’t means forbidden). (B) and (C) are Structural Errors.
5 Key: (A) must
Explanation: – Why it’s correct: This is a strong personal desire coming from your heart (“I love her so much”).
- Distractor Analysis: (B) is a Meaning Trap (“have to” sounds like someone is forcing you to do it against your will). (C) and (D) are Structural Errors.
6 Key: (B) have to
Explanation: – Why it’s correct: The shop closing at 6 PM is an external fact/schedule. You are forced to leave by this external rule, so “have to” is required.
- Distractor Analysis: (A) is a Meaning Trap (too weak for a strict closing time). (C) is a Structural Error. (D) is a Common Mistake (we rarely use “have to” in the continuous form).
7 Key: (C) must
Explanation: – Why it’s correct: A self-reminder to do something sweet. The obligation comes from your own mind.
- Distractor Analysis: (A) is a Meaning Trap (it sounds like a chore or external rule). (B) and (D) are Structural Errors.
8 Key: (D) mustn’t
Explanation: – Why it’s correct: A strong personal rule/prohibition to protect the surprise.
- Distractor Analysis: (A) is a Common Mistake (“don’t have to” means it’s okay if you tell her, which contradicts “She will ruin it”). (B) and (C) are Structural Errors.
9 Key: (A) should
Explanation: – Why it’s correct: The word “Maybe” clearly shows this is just a gentle suggestion/advice from a friend.
- Distractor Analysis: (B) and (C) are Meaning Traps (both are far too strong for a “maybe” suggestion). (D) is a Structural Error.
10 Key: (B) must
Explanation: – Why it’s correct: A strong internal resolution.
- Distractor Analysis: (D) is a Meaning Trap (too weak for this strong personal feeling). (C) is a Common Mistake (missing “to”). (A) is a Structural Error (wrong subject agreement).
11 Key: (C) don’t have to
Explanation: – Why it’s correct: It is not necessary to buy a cake because there is already one.
- Distractor Analysis: (B) is a Common Mistake (“mustn’t” means it is forbidden to buy a cake, which is silly). (A) is a Meaning Trap. (D) is a Structural Error.
12 Key: (D) have to
Explanation: – Why it’s correct: The shop not accepting credit cards is an external rule that forces you to go to the ATM.
- Distractor Analysis: (C) is a Meaning Trap (it’s not an internal feeling; it’s a strict shop policy). (B) is a Meaning Trap (too weak). (A) is a Structural Error.
13 Key: (A) must
Explanation: – Why it’s correct: The obligation comes from personal guilt (“I haven’t visited her in two weeks”) and a sense of duty.
- Distractor Analysis: (B) is a Meaning Trap (“have to” makes visiting your mom sound like a forced chore). (D) is a Meaning Trap (too weak for the guilt implied). (C) is a Structural Error.
14 Key: (B) mustn’t
Explanation: – Why it’s correct: A strong personal promise to yourself not to do something bad (being late).
- Distractor Analysis: (A) is a Common Mistake (means “it’s okay to be late”). (C) and (D) are Structural Errors.
15 Key: (C) should
Explanation: – Why it’s correct: Asking for an opinion or advice on a choice.
- Distractor Analysis: (A) and (B) are Meaning Traps (asking about strict rules, not opinions). (D) is a Structural Error.
16 Key: (D) must
Explanation: – Why it’s correct: Expressing a strong personal duty to be a good son.
- Distractor Analysis: (A) is a Meaning Trap (nobody is forcing you externally to be a good son; it comes from within). (B) and (C) are Structural Errors.
17 Key: (A) don’t have to
Explanation: – Why it’s correct: Tells the person that it is not necessary to rush.
- Distractor Analysis: (B) is a Common Mistake (means “forbidden to rush”). (C) is a Structural Error. (D) is a Structural Error (wrong verb agreement for “you”).
18 Key: (B) must
Explanation: – Why it’s correct: Strong internal determination to make things perfect.
- Distractor Analysis: (A) is a Meaning Trap (sounds like someone else ordered you to do it). (D) is a Meaning Trap (too weak). (C) is a Structural Error.
19 Key: (C) should
Explanation: – Why it’s correct: The friend is giving helpful advice.
- Distractor Analysis: (B) is a Meaning Trap (there is no law requiring you to text first). (A) and (D) are Structural Errors.
20 Key: (D) must
Explanation: – Why it’s correct: A strong final resolution and promise to yourself for the future.
- Distractor Analysis: (A) is a Meaning Trap (an external rule). (B) and (C) are Structural Errors.
GRAMMAR POINTS TO REMEMBER
- Must (Internal Obligation): – We use Must when the feeling of obligation comes from inside the speaker.
- It is used for personal rules, feelings of love, guilt, or strong self-reminders.
- Example: “I love my mom, I must buy her a gift.” (Nobody is pointing a gun at you; your heart is telling you to do it).
- Grammar Rule: Never put “to” after “must”. (Correct: I must go. Incorrect: I must to go).
- Have to (External Obligation): – We use Have to when the obligation comes from the outside world (schedules, rules, laws, closing times, bosses).
- Example: “I have to leave because the shop closes at 6 PM.” (The shop’s clock is forcing you).
- Should (Advice): – We use Should to say something is a good idea. It is a soft obligation.
- Example: “You should buy roses.”
- Mustn’t vs. Don’t have to (Crucial Difference!):
- Mustn’t means PROHIBITION. (It is very bad/dangerous/forbidden to do this). -> “I mustn’t forget!”
- Don’t have to means LACK OF OBLIGATION. (It is not necessary, but you can if you want to). -> “You don’t have to buy a cake.”