Mustn’t vs. Don’t have to – English Grammar Exercises for B1
Choose the best option (A, B, C, or D) to complete each sentence. Read the text carefully, as all questions are part of a continuous orientation given by an HR manager to a new employee.
Welcome to the team! Let me explain our Friday workplace guidelines.
1 On Fridays, we have a special rule to help you relax: you ______ wear a formal suit to the office.
(a) haven’t to
(b) shouldn’t
(c) mustn’t
(d) don’t have to
2 Since it is our “Casual Friday”, you ______ put on a tie unless you have an important meeting with clients.
(a) don’t have to
(b) mustn’t
(c) couldn’t
(d) don’t must
3 However, even on Casual Friday, you ______ wear ripped jeans or flip-flops. That is strictly against company policy.
(a) mustn’t to
(b) don’t have to
(c) mustn’t
(d) aren’t need to
4 The company provides a free catered lunch on Fridays, so you ______ bring your own food from home.
(a) mustn’t
(b) don’t have to
(c) wouldn’t
(d) don’t need
5 But please remember, you ______ eat strongly scented food at your desk because it bothers your coworkers.
(a) mustn’t
(b) not have to
(c) don’t have to
(d) shouldn’t
6 If you prefer wearing formal clothes every day, that is perfectly fine. You ______ dress casually if you don’t want to.
(a) haven’t to dress
(b) don’t have to
(c) mustn’t
(d) aren’t supposed to
7 We want our staff to feel comfortable, so women ______ wear high heels on Fridays.
(a) can’t
(b) don’t have
(c) mustn’t
(d) don’t have to
8 During the casual afternoon break, you ______ talk about work; it’s a time to relax and chat with colleagues.
(a) don’t have to
(b) won’t
(c) mustn’t
(d) don’t must
9 We operate on a flexible schedule on Fridays, meaning you ______ arrive exactly at 8:00 AM, as long as you complete your 8 hours.
(a) mustn’t
(b) don’t have to
(c) haven’t to
(d) shouldn’t
10 Although the atmosphere is very relaxed, you ______ forget to badge in at the security gate for safety reasons.
(a) don’t have to
(b) needn’t
(c) mustn’t
(d) mustn’t to
11 You are allowed to leave early on Friday afternoons, but you ______ leave without telling your direct supervisor first.
(a) mustn’t leaving
(b) couldn’t
(c) don’t have to
(d) mustn’t
12 The IT department runs automatic backups on Friday evenings, so you ______ manually save your files to the external drive.
(a) shouldn’t
(b) don’t have to
(c) mustn’t
(d) aren’t have to
13 However, you ______ share your system password with anyone, even on relaxed days. Security is a top priority.
(a) mustn’t
(b) haven’t to
(c) don’t have to
(d) shouldn’t
14 Our CEO usually buys coffee for everyone on Friday mornings, so you ______ pay for your own espresso today.
(a) aren’t required
(b) mustn’t
(c) don’t have to
(d) don’t need
15 We highly encourage teamwork, but you ______ attend the Friday evening social event if you have personal plans.
(a) don’t have to
(b) are not to
(c) don’t must
(d) mustn’t
16 The only strict rule in this building regards the server room: unauthorized personnel ______ enter that room under any circumstances.
(a) don’t have to
(b) mustn’t to
(c) needn’t
(d) mustn’t
17 As a new hire, you ______ read the entire employee handbook today; take your time and finish it by next week.
(a) shouldn’t
(b) don’t have to
(c) mustn’t
(d) haven’t to
18 Even though we joke around on Fridays, you ______ make any inappropriate or offensive comments to your colleagues.
(a) mustn’t
(b) don’t have to
(c) needn’t
(d) mustn’t making
19 If you finish your weekly tasks early, you ______ start next week’s assignments immediately. Take a break!
(a) don’t have
(b) mustn’t
(c) don’t have to
(d) won’t have
20 Enjoy your Casual Friday, but remember that you ______ let the relaxed dress code affect your professional attitude.
(a) don’t have to
(b) mustn’t
(c) haven’t to
(d) shouldn’t
ANSWER KEY & EXPLANATIONS
1 (d) don’t have to
- Why it is correct: Wearing a suit is an obligation that has been removed for Fridays. It is optional.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake (meaning you are strictly forbidden to wear a suit, which is incorrect). (a) “haven’t to” is a Structural Error. (b) “shouldn’t” is a Meaning Trap.
2 (a) don’t have to
- Why it is correct: You are given the privilege to skip wearing a tie. There is no obligation.
- Distractor Analysis: (b) “mustn’t” is a Common Mistake. (d) “don’t must” is a Structural Error (the negative of must is mustn’t). (c) “couldn’t” is a Meaning Trap.
3 (c) mustn’t
- Why it is correct: Ripped jeans are against company policy. This is a strict prohibition.
- Distractor Analysis: (b) “don’t have to” is a Common Mistake (implies you can wear them if you want, which violates HR policy). (a) “mustn’t to” is a Structural Error (no “to” after modals). (d) “aren’t need to” is a Structural Error.
4 (b) don’t have to
- Why it is correct: The company provides food, so bringing your own is unnecessary.
- Distractor Analysis: (a) “mustn’t” is a Common Mistake (you aren’t forbidden from bringing your own lunch). (d) “don’t need” is a Structural Error (requires “to” -> “don’t need to”). (c) “wouldn’t” is a Meaning Trap.
5 (a) mustn’t
- Why it is correct: Eating smelly food bothers others. This is a behavioral rule/prohibition in the office.
- Distractor Analysis: (c) “don’t have to” is a Common Mistake. (b) “not have to” is a Structural Error. (d) “shouldn’t” is a Meaning Trap (too weak for an HR directive).
6 (b) don’t have to
- Why it is correct: Casual wear is optional. If you don’t want to do it, you lack the obligation to do so.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake. (a) “haven’t to dress” is a Structural Error. (d) “aren’t supposed to” is a Meaning Trap.
7 (d) don’t have to
- Why it is correct: Women are freed from the uncomfortable obligation of wearing high heels.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake. (b) “don’t have” is a Structural Error (missing “to”). (a) “can’t” is a Meaning Trap.
8 (a) don’t have to
- Why it is correct: You are not forced to talk about work during the break; you can talk about other things.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake (you aren’t forbidden from talking about work if you really want to). (d) “don’t must” is a Structural Error. (b) “won’t” is a Meaning Trap.
9 (b) don’t have to
- Why it is correct: The flexible schedule removes the strict 8:00 AM arrival rule.
- Distractor Analysis: (a) “mustn’t” is a Common Mistake. (c) “haven’t to” is a Structural Error. (d) “shouldn’t” is a Meaning Trap.
10 (c) mustn’t
- Why it is correct: Forgetting to badge in is a security violation. It is strictly forbidden.
- Distractor Analysis: (a) “don’t have to” is a Common Mistake (means “you can forget if you want,” which is dangerous). (b) “needn’t” is a Meaning Trap (means “not necessary,” not prohibited). (d) “mustn’t to” is a Structural Error.
11 (d) mustn’t
- Why it is correct: Leaving without telling your boss is a breach of office protocol. It is prohibited.
- Distractor Analysis: (c) “don’t have to” is a Common Mistake. (a) “mustn’t leaving” is a Structural Error (needs bare infinitive). (b) “couldn’t” is a Meaning Trap.
12 (b) don’t have to
- Why it is correct: The IT department does it automatically, so the manual task is unnecessary for you.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake. (d) “aren’t have to” is a Structural Error. (a) “shouldn’t” is a Meaning Trap.
13 (a) mustn’t
- Why it is correct: Sharing passwords is a severe IT security violation. It is absolutely forbidden.
- Distractor Analysis: (c) “don’t have to” is a Common Mistake. (b) “haven’t to” is a Structural Error. (d) “shouldn’t” is a Meaning Trap.
14 (c) don’t have to
- Why it is correct: The CEO pays for the coffee, effectively removing your financial obligation.
- Distractor Analysis: (b) “mustn’t” is a Common Mistake. (d) “don’t need” is a Structural Error (missing “to”). (a) “aren’t required” is a Meaning Trap (structurally, it needs “to pay” after the gap to be fully correct, making “don’t have to” the perfect fit).
15 (a) don’t have to
- Why it is correct: The social event is encouraged but entirely optional.
- Distractor Analysis: (d) “mustn’t” is a Common Mistake. (c) “don’t must” is a Structural Error. (b) “are not to” is a Meaning Trap.
16 (d) mustn’t
- Why it is correct: Entering the server room without authorization is strictly prohibited.
- Distractor Analysis: (a) “don’t have to” is a Common Mistake. (b) “mustn’t to” is a Structural Error. (c) “needn’t” is a Meaning Trap.
17 (b) don’t have to
- Why it is correct: There is no rush; the obligation to finish reading it today does not exist.
- Distractor Analysis: (c) “mustn’t” is a Common Mistake. (d) “haven’t to” is a Structural Error. (a) “shouldn’t” is a Meaning Trap.
18 (a) mustn’t
- Why it is correct: Offensive comments are a violation of workplace harassment policies. They are forbidden.
- Distractor Analysis: (b) “don’t have to” is a Common Mistake (implies “you don’t have to offend people, but you can,” which is legally and morally wrong). (d) “mustn’t making” is a Structural Error. (c) “needn’t” is a Meaning Trap.
19 (c) don’t have to
- Why it is correct: You are free to take a break; you are not obligated to start new work right away.
- Distractor Analysis: (b) “mustn’t” is a Common Mistake. (a) “don’t have” is a Structural Error. (d) “won’t have” is a Meaning Trap.
20 (b) mustn’t
- Why it is correct: Letting your attitude drop is unacceptable in a professional environment. It is a strict warning.
- Distractor Analysis: (a) “don’t have to” is a Common Mistake. (c) “haven’t to” is a Structural Error. (d) “shouldn’t” is a Meaning Trap (often used for advice, but “mustn’t” conveys the firm HR rule).
GRAMMAR POINTS TO REMEMBER
1 DON’T HAVE TO (The Removal of an Obligation):
- Meaning: It is NOT necessary to do this. A rule has been relaxed, or someone else has done the work for you. You have the freedom to choose.
- Workplace Context: You don’t have to wear a tie (the dress code rule is paused). You don’t have to pay for coffee (the CEO paid).
- Structure: Subject + don’t/doesn’t have to + Verb (bare infinitive).
2 MUSTN’T (The Strict Rule / Prohibition):
- Meaning: Do NOT do this under any circumstances. It is against company policy, illegal, or dangerous. You have no choice.
- Workplace Context: You mustn’t wear flip-flops. You mustn’t share your password. You mustn’t leave without telling your boss.
- Structure: Subject + mustn’t + Verb (bare infinitive). (Never use “to” after mustn’t).
The HR Rule of Thumb: If HR is giving you a perk or a break, they use “don’t have to”. If HR is protecting the company’s safety or reputation, they use “mustn’t”.