This third mixed modals exercise practices can, should, and must in natural everyday contexts. The key is identifying what the sentence is really expressing — ability, advice, or logical deduction — and matching that to the right modal. Start with exercise 1 if you haven’t already.
Choose the modal verb that best completes each sentence.
1. You look pretty tired. I think you ________ rest.
Correct answer: should
2. Mary hasn't eaten since this morning. She ________ be very hungry!
Correct answer: must
3. We ________ leave anytime you want.
Correct answer: can
4. ________ you please ask the neighbor to turn down his music?
Correct answer: Can
5. This is a dangerous neighborhood. You ________ be careful here.
Correct answer: should
6. I have to see if I ________ leave my car here overnight.
Correct answer: can
7. Oliver ________ have been so upset that his team lost!
Correct answer: must
8. My father ________ believe that I aced all my exams.
Correct answer: can't
9. William isn't sure if he ________ buy his mom flowers or something else.
Correct answer: should
10. How ________ they afford such an expensive apartment?
Correct answer: can
—
Grammar reviewCan, should and must — choosing the most natural option
This exercise asks you to choose the more natural-sounding modal. That is a different skill from simply knowing the grammar rules — it requires understanding how native speakers actually use these words in everyday conversation.
Context clues that point to must:
When a sentence describes something that is almost certainly true based on evidence or logic: He didn't answer any calls all weekend. He ________ be busy. (logical deduction)
Context clues that point to can:
When a sentence describes what someone is or isn’t able to do: She's fluent in three languages. She ________ switch between them easily.
Context clues that point to should:
When a sentence offers a recommendation, warning, or suggestion: Your eyes are red. You ________ take a break from the screen.
Did you know?
Unlike most English proficiency tests, the Cambridge English Qualifications include a dedicated grammar section called “Use of English.” This appears in the FCE (B2 First), CAE (C1 Advanced), and CPE (C2 Proficiency) exams and tests grammar and vocabulary directly through tasks such as multiple-choice cloze, open cloze, word formation, and sentence transformations. If you’re preparing for a Cambridge exam, targeted grammar practice — including modal verbs — is essential.