Modals of Obligation (Must, Have to, Should) – English Grammar Exercises for A2
You are sitting in a classroom. Your teacher is standing at the front, handing out the final exam papers and giving strict, direct commands. Read the sentences carefully and choose the best option (A, B, C, or D) to complete each instruction.
1 “Welcome to the final exam. You ______ write your name at the top of the paper immediately.”
(A) must to
(B) must
(C) should
(D) have
2 “The test begins now. You ______ talk to your classmates during the exam.”
(A) mustn’t
(B) don’t have to
(C) shouldn’t
(D) not must
3 “If you have a question, you ______ raise your hand and wait for me to come to your desk.”
(A) must
(B) must to
(C) should
(D) are must
4 “You ______ use a black or blue pen. Pencils are absolutely not allowed.”
(A) have
(B) should
(C) must
(D) musts
5 “You ______ leave the room before the exam finishes. Everyone stays until the bell rings.”
(A) shouldn’t
(B) don’t have to
(C) haven’t to
(D) mustn’t
6 “I am giving you exactly 60 minutes. You ______ stop writing when I say ‘Time is up’.”
(A) should
(B) have
(C) must
(D) must to
7 “Students, listen to me carefully: you ______ bring any phones or smartwatches to your desks.”
(A) don’t have to
(B) mustn’t
(C) shouldn’t
(D) aren’t must
8 “If you finish early, you ______ sit quietly in your seat and review your answers.”
(A) must
(B) should
(C) must to
(D) have
9 “You ______ open the test booklet until I tell you to do so. Keep it closed.”
(A) don’t have to
(B) shouldn’t
(C) mustn’t
(D) not must
10 “Every student ______ hand in the paper to me before leaving the classroom.”
(A) musts
(B) must
(C) should
(D) have
11 “I want to be very clear: you ______ look at another student’s paper. That is cheating.”
(A) mustn’t
(B) shouldn’t
(C) don’t have to
(D) haven’t to
12 “You ______ write clearly so that I can read your answers. If I can’t read it, I can’t grade it.”
(A) should to
(B) have
(C) must
(D) must to
13 “Student: ______ write the date on the paper as well?” – “Teacher: Yes, you must.”
(A) Must I
(B) Do I must
(C) Should I
(D) Have I
14 “You ______ forget to check the back of the page. There are three more questions there.”
(A) don’t have to
(B) shouldn’t
(C) mustn’t
(D) not must
15 “I am your teacher, and I say you ______ follow these rules strictly to pass the course.”
(A) should
(B) must
(C) must to
(D) having to
16 “You ______ answer all the questions. Do not leave any blank spaces on your test.”
(A) must
(B) should
(C) have
(D) musts
17 “This is a vocabulary test, so you ______ use a dictionary. Close your books now.”
(A) don’t have to
(B) mustn’t
(C) shouldn’t
(D) haven’t to
18 “You ______ ask to go to the bathroom during the first 30 minutes. It is a strict school policy.”
(A) don’t have to
(B) shouldn’t
(C) aren’t must
(D) mustn’t
19 “You ______ bring your own eraser and ruler. I will not give you any during the test.”
(A) should
(B) must
(C) must to
(D) have
20 “Finally, you ______ believe in yourselves and do your best! Good luck.”
(A) must
(B) musts
(C) should to
(D) have
ANSWER KEY & EXPLANATIONS
1 Key: (B) must
Explanation: – Why it’s correct: “Must” is used to give a direct, authoritative command from the speaker (the teacher).
- Common Mistake (A): Never put “to” after “must”.
- Meaning Trap (C): “Should” is just advice. Writing your name on an exam is a mandatory rule, not a suggestion.
- Structural Error (D): “Have” requires “to” (have to) to show obligation.
2 Key: (A) mustn’t
Explanation: – Why it’s correct: “Mustn’t” means prohibition (it is strictly forbidden to talk).
- Meaning Trap (B): “Don’t have to” means it is optional (you don’t have to talk, but you can if you want), which is completely wrong for an exam!
- Meaning Trap (C): “Shouldn’t” is too weak for a strict exam rule.
- Structural Error (D): “Not must” is the wrong word order.
3 Key: (A) must
Explanation: – Why it’s correct: A direct rule from the teacher.
- Common Mistake (B): “Must to” is grammatically invalid.
- Meaning Trap (C): “Should” is too soft for a classroom procedure commanded by the teacher.
- Structural Error (D): You cannot combine “are” with “must”.
4 Key: (C) must
Explanation: – Why it’s correct: Gives a strict instruction about allowed materials.
- Meaning Trap (B): “Should” implies you can use a pencil if you really want to, which contradicts “absolutely not allowed”.
- Structural Error (A): Missing “to”.
- Structural Error (D): “Must” never takes an “s”.
5 Key: (D) mustn’t
Explanation: – Why it’s correct: Leaving the room is strictly forbidden.
- Meaning Trap (B): “Don’t have to” means leaving is not required, but you could if you wanted.
- Meaning Trap (A): “Shouldn’t” is advice, not a ban.
- Structural Error (C): “Haven’t to” is not standard English.
6 Key: (C) must
Explanation: – Why it’s correct: The teacher is imposing their own authority (“when I say…”). “Must” is perfect for top-down commands.
- Meaning Trap (A): “Should” is too weak.
- Structural Error (B): “Have” lacks “to”.
- Common Mistake (D): “Must to”.
7 Key: (B) mustn’t
Explanation: – Why it’s correct: Phones are prohibited in exams.
- Meaning Trap (A): “Don’t have to” means it’s your choice.
- Meaning Trap (C): “Shouldn’t” is just friendly advice.
- Structural Error (D): “Aren’t must” is invalid.
8 Key: (A) must
Explanation: – Why it’s correct: A direct command from the teacher on how to behave.
- Meaning Trap (B): “Should” is too soft for exam conditions.
- Common Mistake (C): “Must to”.
- Structural Error (D): Missing “to”.
9 Key: (C) mustn’t
Explanation: – Why it’s correct: A strict prohibition against opening the booklet early.
- Meaning Trap (A): “Don’t have to” gives the student a choice.
- Meaning Trap (B): “Shouldn’t” is weak advice.
- Structural Error (D): “Not must”.
10 Key: (B) must
Explanation: – Why it’s correct: “Every student” takes “must” (modals do not change form for singular/plural).
- Structural Error (A): “Musts” is invalid (modals never take ‘s’).
- Meaning Trap (C): “Should” is too weak for handing in a final exam.
- Structural Error (D): “Have” is plural and lacks “to”.
11 Key: (A) mustn’t
Explanation: – Why it’s correct: Cheating is strictly forbidden.
- Meaning Trap (B): “Shouldn’t” is far too weak for cheating.
- Meaning Trap (C): “Don’t have to” means you are not forced to look at someone’s paper (but implies you could).
- Structural Error (D): “Haven’t to”.
12 Key: (C) must
Explanation: – Why it’s correct: A strict requirement from the grader.
- Common Mistake (D): “Must to”.
- Structural Error (B): “Have” lacks “to”.
- Structural Error (A): “Should to” is invalid.
13 Key: (A) Must I
Explanation: – Why it’s correct: To ask a question with “must”, invert the modal and the subject.
- Common Mistake (B): We do not use “Do” to make questions with “must”.
- Meaning Trap (C): “Should I” asks for an opinion, but the student is asking about a strict rule.
- Structural Error (D): “Have I” requires “to”.
14 Key: (C) mustn’t
Explanation: – Why it’s correct: A strong warning/rule from the teacher not to do something.
- Meaning Trap (A): “Don’t have to” means it’s okay if you forget.
- Meaning Trap (B): “Shouldn’t” is too soft.
- Structural Error (D): “Not must”.
15 Key: (B) must
Explanation: – Why it’s correct: The phrase “I am your teacher, and I say…” clearly shows the obligation comes directly from the speaker’s authority.
- Meaning Trap (A): “Should” is advice.
- Common Mistake (C): “Must to”.
- Structural Error (D): “Having to”.
16 Key: (A) must
Explanation: – Why it’s correct: A direct command to complete all questions.
- Meaning Trap (B): “Should” is a recommendation.
- Structural Error (C): “Have” lacks “to”.
- Structural Error (D): “Musts” is invalid.
17 Key: (B) mustn’t
Explanation: – Why it’s correct: Dictionaries are forbidden during a vocabulary test.
- Meaning Trap (A): “Don’t have to” means it is optional.
- Meaning Trap (C): “Shouldn’t” is weak.
- Structural Error (D): “Haven’t to”.
18 Key: (D) mustn’t
Explanation: – Why it’s correct: A strict prohibition against leaving the room early.
- Meaning Trap (A): “Don’t have to” removes the obligation.
- Meaning Trap (B): “Shouldn’t” is weak.
- Structural Error (C): “Aren’t must” is invalid.
19 Key: (B) must
Explanation: – Why it’s correct: A strict instruction regarding required materials.
- Meaning Trap (A): “Should” is too soft.
- Common Mistake (C): “Must to”.
- Structural Error (D): “Have” lacks “to”.
20 Key: (A) must
Explanation: – Why it’s correct: “Must” can also be used by an authority figure to give very strong, encouraging advice (“You must believe in yourselves!”).
- Structural Error (B): “Musts” is invalid.
- Structural Error (C): “Should to” is invalid.
- Structural Error (D): “Have” lacks “to”.
GRAMMAR POINTS TO REMEMBER
- Must (Authority & Direct Commands): – We use Must when the person speaking is the one making the rule. In a classroom, when a teacher says “You must write your name”, they are using their authority to force you to do it. It is stronger and more direct than have to.
- Grammar Rule: Never put “to” after “must”. Never add an “s” to “must”.
- Mustn’t vs. Don’t have to (The Golden Rule):
- Mustn’t (Must not): Means PROHIBITION. It is strictly forbidden. You have no choice.
- Example: “You mustn’t talk.” (If you talk, you fail the exam).
- Don’t have to: Means NOT NECESSARY. You have a choice.
- Example: “You don’t have to finish early.” (You can finish early if you want, but you are not forced to).
- Must vs. Should:
- Use Must for strict rules and commands that cannot be broken.
- Use Should for friendly advice or recommendations. A teacher giving a final exam will use Must for the rules, not Should.