Modals of Obligation (Must, Have to, Should) – English Grammar Exercises for A2
You are a senior employee explaining the company rules and dress code to a new colleague. Read the sentences carefully and choose the best option (A, B, C, or D) to complete each explanation.
1 “Welcome to the team! In this office, we ______ wear a uniform from Monday to Thursday.”
(A) must to
(B) should
(C) have to
(D) has to
2 “Our boss is very strict about time. He says everyone ______ arrive by 8:45 AM.”
(A) has to
(B) have to
(C) must to
(D) should
3 “On Fridays, we ______ wear a suit. You can wear jeans and a t-shirt!”
(A) haven’t to
(B) don’t have to
(C) mustn’t
(D) shouldn’t
4 “New employee: ______ wear a tie every day?”
(A) Have I to
(B) Must I to
(C) Do I have to
(D) Should I to
5 “You don’t have to bring your own coffee, but you ______ wash your cup after using it. It’s polite.”
(A) should
(B) must to
(C) have
(D) don’t have to
6 “I really hate these heavy safety shoes, but I ______ wear them in the warehouse. It’s the law.”
(A) am having to
(B) have to
(C) should
(D) has to
7 “The IT manager ______ wear a uniform because he works in the server room, but the rest of us do.”
(A) hasn’t to
(B) mustn’t
(C) doesn’t have to
(D) don’t have to
8 “This is a formal office. You ______ wear shorts or sandals. It is strictly forbidden.”
(A) don’t have to
(B) shouldn’t
(C) mustn’t
(D) aren’t have to
9 “You ______ wear a blue shirt, but I think it looks very professional for the meeting.”
(A) mustn’t
(B) don’t have to
(C) haven’t to
(D) shouldn’t
10 “All new employees ______ read the company rulebook on their first day.”
(A) has to
(B) should
(C) must to
(D) have to
11 “New employee: ______ the receptionist have to wear a name tag?”
(A) Does
(B) Do
(C) Has
(D) Is
12 “We ______ clock in before 9:00 AM. That is the computer system’s rule.”
(A) have to
(B) must to
(C) should
(D) has to
13 “It can get cold in the office. You ______ keep a sweater at your desk.”
(A) have to
(B) should to
(C) should
(D) must to
14 “I ______ wear these safety glasses because the factory supervisor is watching me.”
(A) must to
(B) having to
(C) should
(D) have to
15 “Yesterday, the big boss visited the office. We all ______ wear our best suits.”
(A) have to
(B) had to
(C) must
(D) should
16 “What ______ do if I lose my ID card?” – “You have to tell security immediately.”
(A) do I have to
(B) have I to
(C) I should
(D) must I to
17 “You ______ work late tonight. The project is already finished, so go home and rest!”
(A) mustn’t
(B) aren’t have to
(C) don’t have to
(D) shouldn’t to
18 “I don’t like wearing this uniform, but the company policy says I ______.”
(A) should
(B) must
(C) has to
(D) have to
19 “If you meet clients, you ______ wear a jacket, but if you stay in the office, you ______.”
(A) have to / doesn’t have to
(B) have to / don’t have to
(C) must to / haven’t to
(D) should / mustn’t
20 “You ______ park in the CEO’s parking space. It is strictly forbidden. However, you ______ pay for the employee parking; it is free.”
(A) don’t have to / mustn’t
(B) mustn’t / shouldn’t
(C) mustn’t / don’t have to
(D) shouldn’t / haven’t to
ANSWER KEY & EXPLANATIONS
1 Key: (C) have to
Explanation: – Why it’s correct: “Have to” is used to state an external rule or obligation (the company’s dress code).
- Common Mistake (A): “Must” is never followed by “to”.
- Meaning Trap (B): “Should” means it is good advice, but a uniform is a strict rule, not a suggestion.
- Structural Error (D): “Has to” is incorrect for the subject “we”.
2 Key: (A) has to
Explanation: – Why it’s correct: “Everyone” is treated as a singular subject, so it takes “has to”. It expresses the boss’s strict rule.
- Structural Error (B): “Have to” is plural.
- Common Mistake (C): “Must to” is always incorrect.
- Meaning Trap (D): “Should” is too weak for a strict boss.
3 Key: (B) don’t have to
Explanation: – Why it’s correct: “Don’t have to” means there is NO obligation (it is not necessary to wear a suit).
- Common Mistake (C): “Mustn’t” means it is forbidden/prohibited to wear a suit, which is incorrect here (you can wear one if you want, but you are not forced to).
- Structural Error (A): “Haven’t to” is grammatically invalid.
- Meaning Trap (D): “Shouldn’t” means it is bad advice.
4 Key: (C) Do I have to
Explanation: – Why it’s correct: In the Present Simple, we form questions with “Do/Does + subject + have to”.
- Common Mistake (B): “Must I to” adds an illegal “to” after must.
- Structural Error (A): Treating “have” as an auxiliary instead of a main verb.
- Structural Error (D): “Should I to” is incorrect.
5 Key: (A) should
Explanation: – Why it’s correct: Washing your cup is polite and a good idea, making it a piece of friendly advice (“should”).
- Common Mistake (B): “Must to” is invalid.
- Structural Error (C): Missing “to”.
- Meaning Trap (D): “Don’t have to” means it’s not necessary, which contradicts “It’s polite”.
6 Key: (B) have to
Explanation: – Why it’s correct: The speaker dislikes the shoes but wears them because of an external force (“the law”). “Have to” perfectly captures this lack of personal choice.
- Common Mistake (A): We generally do not use “have to” in the continuous form (“am having to”) for general rules.
- Meaning Trap (C): “Should” is too weak for the law.
- Structural Error (D): “Has to” is wrong for “I”.
7 Key: (C) doesn’t have to
Explanation: – Why it’s correct: “The IT manager” is singular, so we use “doesn’t have to” to show he is free from this rule.
- Structural Error (D): “Don’t” is plural.
- Structural Error (A): “Hasn’t to” is invalid.
- Meaning Trap (B): “Mustn’t” means he is forbidden to wear it.
8 Key: (C) mustn’t
Explanation: – Why it’s correct: “Mustn’t” is used for strict prohibitions (“strictly forbidden”).
- Common Mistake (A): “Don’t have to” means it’s okay if you want to wear shorts, which is completely wrong here.
- Meaning Trap (B): “Shouldn’t” is just advice; it is not strong enough for a strict prohibition.
- Structural Error (D): “Aren’t have to” is invalid grammar.
9 Key: (B) don’t have to
Explanation: – Why it’s correct: It is not a rule to wear a blue shirt (no obligation), but it is recommended.
- Common Mistake (A): “Mustn’t” means it’s forbidden.
- Meaning Trap (D): “Shouldn’t” means it is a bad idea.
- Structural Error (C): “Haven’t to” is invalid.
10 Key: (D) have to
Explanation: – Why it’s correct: “All new employees” is plural, taking “have to” for a company requirement.
- Structural Error (A): “Has to” is singular.
- Meaning Trap (B): “Should” implies they can choose not to read it, which isn’t true for a company rulebook.
- Common Mistake (C): “Must to” is invalid.
11 Key: (A) Does
Explanation: – Why it’s correct: “The receptionist” is a third-person singular subject, requiring the auxiliary “Does” to form the question.
- Structural Error (B): “Do” is for plural subjects.
- Structural Error (C): “Has” cannot be used to form questions with “have to”.
- Structural Error (D): “Is” cannot be used with the main verb “have”.
12 Key: (A) have to
Explanation: – Why it’s correct: Expresses an external obligation imposed by the system.
- Common Mistake (B): “Must to” is invalid.
- Meaning Trap (C): “Should” is too weak.
- Structural Error (D): “Has to” is wrong for “We”.
13 Key: (C) should
Explanation: – Why it’s correct: Bringing a sweater is a personal recommendation to stay warm, not a company rule.
- Meaning Trap (A): “Have to” would mean the boss forces you to bring a sweater.
- Structural Error (B): “Should to” is invalid.
- Common Mistake (D): “Must to” is invalid.
14 Key: (D) have to
Explanation: – Why it’s correct: The obligation comes entirely from the outside (the supervisor watching).
- Common Mistake (A): “Must to” is invalid.
- Structural Error (B): Missing the “be” verb, and “have to” is rarely continuous.
- Meaning Trap (C): “Should” is for advice, not strict supervision.
15 Key: (B) had to
Explanation: – Why it’s correct: “Yesterday” indicates the past. The past tense of both “must” and “have to” is “had to”.
- Structural Error (A): “Have to” is present tense.
- Common Mistake (C): “Must” has no past tense form.
- Meaning Trap (D): “Should” does not express a past obligation.
16 Key: (A) do I have to
Explanation: – Why it’s correct: Correct question format (Wh-word + do/does + subject + have to).
- Structural Error (B): “Have I to” is incorrect.
- Common Mistake (D): “Must I to” adds an illegal “to”.
- Structural Error (C): “I should” is statement word order, not a question.
17 Key: (C) don’t have to
Explanation: – Why it’s correct: Removes the obligation to work late. “It is not necessary.”
- Common Mistake (A): “Mustn’t” means it is forbidden to work late.
- Structural Error (B): “Aren’t have to” is invalid.
- Structural Error (D): “Shouldn’t to” is invalid.
18 Key: (D) have to
Explanation: – Why it’s correct: The speaker doesn’t want to do it, but “company policy” (external force) makes it mandatory.
- Meaning Trap (B): “Must” implies the speaker internally agrees with the rule, but the context shows they don’t.
- Meaning Trap (A): “Should” is too weak for a policy.
- Structural Error (C): “Has to” is wrong for “I”.
19 Key: (B) have to / don’t have to
Explanation: – Why it’s correct: First part is a rule (have to). Second part removes the rule (don’t have to).
- Structural Error (A): “Doesn’t” is wrong for “you”.
- Structural Error (C): “Must to” and “haven’t to” are both grammatically invalid.
- Meaning Trap (D): “Mustn’t” would mean it is forbidden to wear a jacket in the office, which is unlikely.
20 Key: (C) mustn’t / don’t have to
Explanation: – Why it’s correct: First gap is a strict prohibition (mustn’t = forbidden to park there). Second gap is a lack of obligation (don’t have to = it is not necessary to pay because it is free).
- Common Mistake (A): Swaps the meanings. You can’t say “you don’t have to park in the CEO space” (meaning you can if you want).
- Meaning Trap (B): “Shouldn’t” is too weak for something that is free.
- Structural Error (D): “Haven’t to” is invalid.
GRAMMAR POINTS TO REMEMBER
- Have to (External Rules): – We use “have to” when the obligation comes from the outside world (like a boss, the law, or company policy).
- Example: “I have to wear a uniform.” (I don’t choose this; the company forces me).
- Must vs. Have to: – Must is for internal feelings (“I must buy my mom a gift”).
- Have to is for external rules. In a workplace, you will mostly use “have to” to explain rules to others. Note: NEVER say “must to”.
- Mustn’t vs. Don’t have to (Crucial Difference):
- Mustn’t means PROHIBITION. You are strictly forbidden to do it. (You mustn’t wear sandals.)
- Don’t have to means NOT NECESSARY. You have a choice. (You don’t have to wear a tie on Fridays.)
- Questions:
- Always use Do/Does to make questions with “have to”.
- Right: Do we have to wear a suit?
- Wrong: Have we to wear a suit?