Perfect Modals
Essential Question
How do we express regret, possibility, and advice about things that happened in the past?
Grammar in the World
What Do I Know?
Use the interactive below to find out how much you already know about perfect modals:
Building Blocks
Grammar is a complex system and structure of language. Mizzou Academy Grammar Lab spotlights one skill (or block) at a time, but it’s often helpful to see how a skill works together with other, related blocks to build the language structure as a whole. You may find the following resource topics helpful as context for this lesson:
- Verbs
- Verb Tenses
- Subject-Verb Agreement (Auxiliary Verbs and Questions)
- When and Why To Use Modals
- Progressive Modals
Learn About Perfect Modals
In Group 2, When and Why To Use Modals, you can see an overview of the 9 main modal verbs and how to use them. Take time to review that topic now if you have not already.
Perfect Modals
Perfect modals have different meanings than ordinary modals. Perfect Modals help us talk about events that either happened in the past, could have happened in the past, or should have happened in the past.
Ability, Permission, or Possibility
- could, might, and may are the most common modals used for ability, permission, and possibility.
Notice how this one sentence could be interpreted three different ways:
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She could have stayed out late with her friends last night. |
- Ability. She had the ability to stay out late last night. Perhaps she was wide awake, had her own car, or had nothing to do early the next morning.
- Permission. She had permission to stay out late last night. Perhaps her parents told her it was okay to stay out past her curfew.
- Possibility: It’s possible that she stayed out late last night. Perhaps we haven’t seen her yet this morning, and we think she could have stayed out late. Or, perhaps we mean that it was possible she would stay out late last night but she changed her mind.
Notice that we can also use “might” and “may” for similar meanings:
- She might have stayed out late with her friends last night.
- She may have stayed out late with her friends last night.
Advice
- “Should” is the most common modal used to give advice; “ought to” and “had better” can be used, as well.
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I should have watered my plants more often. He ought to have been home by now. |
Regret
- “Would” is the most common modal to share regret.
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He would have studied more for the test if he had more time. I would have made more food if I had known you were coming over. They would have chosen a different movie to watch if they had realized this one was so scary! |
Deduction–something we are fairly sure happened based on what we already know.
- “Must” is the most common model for this purpose. You will also see “will.”
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You must have spent all day baking; there’s enough food here to serve 30 people! We must have read the invitation wrong; there is no one else here. It must be very slick outside; school is canceled. You will have spent all day reading by the time you finish that book! He will have spent all of his money if he buys that huge Lego set. |
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Perfect Modals |
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modal + have + past participle |
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must |
have |
practiced |
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might |
have |
read |
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will |
have |
studied |
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could |
have |
slept |
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should |
have |
reviewed |
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may |
have |
asked |
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must |
have |
tried |
Note: the modal “can” is not used when forming perfect modals. “Can have slept” does not make sense. Instead, use the modal “could.”
Examples
Now that you have learned about perfect modals, review these examples to see the different purposes perfect modals have.
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Perfect Modals |
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modal + have + past participle |
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Purpose |
Modals |
Example |
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Ability |
Could, Might, May |
They could have bought a new house if they had found one they liked. |
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Permission |
Could, Might, May |
She may borrow her brother’s car for the weekend. |
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Possibility |
Could, Might, May |
We might drive to the beach this weekend. |
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Advice |
Should, Ought to, Had better |
We should eat at the new Italian restaurant tonight. |
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Regret |
Would |
I would have eaten fewer breadsticks if I had known the lasagna was so good! |
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Deduction |
Must |
You must really love lasagna; you asked for another serving. |
Questions and Perfect Modals
You can form a question with perfect modals by using this pattern:
modal + subject + have + past participle
Notice how we change each statement into a question with this pattern:
Statement: We should eat at the new Italian restaurant.
Question: Should we eat at the new Italian restaurant?
Statement: I would have eaten fewer breadsticks if I had known the lasagna was so good!
Question: Would you have eaten fewer breadsticks if you had known the lasagna was so good?
Negative Statements and Perfect Modals
Any statement with a perfect modal can be changed to a negative by using the word “not.”
- She may not borrow her brother’s car for the weekend.
- We might not drive to the beach this weekend.
- You must not really love lasagna; you barely touched your food.
Do I Get It?
Use the interactive exercise below to test your knowledge of perfect modals: