C1 English Grammar – Modal Verbs – Ex 29

What Are Modal Verbs?

Modal verbs are auxiliary (helping) verbs that express attitudes toward the main verb. They never change form (no -s, -ing, or -ed), and are followed by a base verb (without "to").

Core modals: can, could, may, might, must, shall, should, will, would

Key features:

• No third-person -s: “She can swim” (not *“She cans swim”)
• No infinitive or participle forms: you say “be able to” instead of “to can”
• Form questions and negatives without “do”: “Can she swim?” / “She cannot swim.”

Meanings and Uses

Each modal has multiple meanings depending on context. At C1, you must choose the right one for tone and precision.

• Ability: can (present), could (past) – “I can speak French.”
• Permission: can, may, could (formal) – “May I leave early?”
• Obligation: must (internal), have to (external) – “You must study.” / “I have to work.”
• Prohibition: must not, cannot – “You must not enter.”
• Advice: should, ought to – “You should apologize.”
• Possibility: may, might, could – “It might rain.”
• Deduction: must (certainty), can’t (impossibility) – “She must be tired.” / “That can’t be true.”
• Hypotheticals: would, could, might – “I would travel if I had time.”

Perfect Modals (C1 Focus)

Modal + have + past participle expresses past meaning—often for speculation, regret, or criticism.

• Should have + past participle: regret or missed opportunity – “I should have studied harder.”
• Must have + past participle: logical conclusion about the past – “She must have forgotten.”
• Could have + past participle: past ability not used, or possibility – “He could have won.”
• Might have + past participle: uncertain past possibility – “They might have missed the train.”
• Can’t have + past participle: impossibility in the past – “He can’t have stolen it.”

Note: “Mustn’t have” is not standard English for past prohibition. Use “shouldn’t have” instead.

Core Modal Verbs:

correct “She must be exhausted after that trip.”
incorrect “She must to be exhausted.” — modals are never followed by “to”

How This Quiz Works

• 20 questions randomly selected from a pool of 50
• Tests meaning, form, perfect modals, and subtle distinctions (e.g., may vs. might, must vs. have to)
• Hints guide you without revealing the answer
• Immediate feedback: correct or incorrect with clear explanations
• Click “Check Answers” to view the full answer key
• “Change Questions” gives you a new set