Modal Verbs of Deduction about The Past - must, might, may, could, can't, couldn't
International English Language Testing System ( IELTS )
Modal verbs are special helper verbs. They show necessity, possibility, permission, or ability.
Some modal verbs of deduction are:
- I must finish this project.
- She might join us for dinner.
- They can't be serious about that idea.
In these examples, must, might, and can't tell how sure we are about something.
Learning modal verbs of deduction is very important for speaking and writing English, especially at B2 CEFR level, They help us say how likely something is. This also helps in IELTS speaking and writing.
Using modal verbs of deduction helps us explain our thinking and assumptions. For example, in job interviews or school discussions, they help us sound more confident. Modal verbs are very useful because they help us show our ideas and conclusions clearly. In this article, you will learn what modal verbs of deduction are, how to use them in sentences, the different levels of certainty, and examples.
What are the Modal Verbs of Deduction?
Modal verbs of deduction help you express how sure or unsure you’re of something. These verbs allow you to make guesses using info. you have. Some most common modal verbs for deduction are - must, might, may, could, can't and couldn't.
Deduction means you think and make conclusion using facts or proof.
For example - if someone sees dark clouds they can guess it may rain soon. However your surity depends on facts or info. you hold.
Structure of Modal Verbs for Deduction
The structure of modal verbs of deduction depends on whether they refer to the present or the past.
Present Deductions
- Structure: Subject + Modal Verb + Base Form of Verb
- Example: "She must be tired."
Past Deductions
- Structure: Subject + Modal Verb + have + Past Participle
- Example: "They must have left early."
How to use Modal Verbs for Deduction?
We use modal verbs for deduction to guess if something is true using the info we have. The modal verb shows how sure we are. This is about guessing things now or in the future.
Must
- We use must when we are sure something is true or the only logical choice.
- That must be her office. I see her name on the door.
Might, May, Could
- He is not home yet. He could be running some errands.
- We may have delays because of the storm.
- All three verbs mean almost same, but may is more formal than might or could.
Can't
- We use can't when something is impossible.
- It can't be far. The map shows we are almost there.
- He can't have forgotten the appointment. I reminded him two times!
- She can't be happy with the decision. She argued before it.
All modal verbs are followed by a verb in base form without to.
Examples of Modal Verbs in Sentences
| Modal Verb |
Use / Meaning |
Examples |
|---|---|---|
| Must |
Strong certainty / sure about something |
She must be at the office; her car is outside. You must try the chocolate cake; it is really tasty. |
| Might / May / Could |
Possible / not sure |
He might come to the party if he finishes work. We may go hiking this weekend if weather is good. |
| Can't / Couldn't |
Impossible / strong no |
It can't be raining; I checked the weather. He couldn't have finished that project alone, it too big. |
| Should / Ought To |
Advice / recommendation |
You should see a doctor if feeling sick. You ought to apologize for your mistake soon. |
| Would |
Politeness / hypothetical |
I would love to join you for dinner. If I had more time, I would travel more often. |
Modal Verbs of Deduction Exercise 1: Complete the Sentences
Fill in the blanks with the appropriate modal verb of deduction (must, might, could, can't) based on the context provided.
1. Given that she has been studying for weeks, she _______ have done well on her exam.
Answer: must
Explanation: "Must" indicates a strong likelihood based on her preparation, suggesting that it is reasonable to conclude she did well.
2. The streets are empty; it _______ be that everyone is at the festival.
Answer: might
Explanation: "Might" suggests a possibility without certainty, indicating that the emptiness could be due to the festival.
3. He didn’t respond to my message; he _______ not have seen it yet.
Answer: can’t
Explanation: "Can’t" indicates a strong deduction that he likely has not seen the message since he didn't respond.
4. She’s wearing a heavy jacket; it _______ be quite chilly outside.
Answer: must
Explanation: "Must" implies a logical conclusion that it is chilly outside because she is wearing a heavy jacket.
5. The report is due today, so he _______ have submitted it already.
Answer: must
Explanation: "Must" indicates a logical conclusion based on the deadline; if he is responsible, he likely submitted it.
Modal Verbs of Deduction Exercise 2: Choose the Correct Modal Verb
Select the correct modal verb of deduction from the options provided.
1. She’s been working late every night; she _______ be under a lot of pressure at work.
Answer: must
Explanation: "Must" indicates a strong conclusion based on her working late, suggesting significant pressure at work.
2. He’s not answering his phone; he _______ be in a meeting right now.
Answer: might
Explanation: "Might" suggests a possibility without certainty regarding his current situation.
3. They didn’t attend the conference; they _______ have had other commitments.
Answer: might
Explanation: "Might" indicates that their absence from the conference could be due to other commitments but does not confirm it.
4. The lights are on in his office; he _______ still be working late.
Answer: must
Explanation: "Must" implies that since the lights are on, it is very likely he is still working.
5. I heard her talking about a new project; she _______ have received funding for it.
Answer: might
Explanation: "Might" suggests a possibility regarding her funding situation based on her discussion about a new project.
Modal Verbs of Deduction Exercise 3: Rewrite the Sentences
Rewrite each sentence using a different modal verb of deduction while maintaining its meaning.
1. She must be very talented; her paintings are exquisite.
Answer: She might be very talented; her paintings are exquisite.
Explanation: Changing "must" to "might" softens the assertion while still implying talent based on her work's quality.
2. He can’t be serious about quitting his job; he has worked there for years.
Answer: He might be serious about quitting his job; he has worked there for years.
Explanation: Changing "can’t" to "might" introduces uncertainty about his seriousness regarding quitting.
3. They might not have received my email about the meeting.
Answer: They must have received my email about the meeting.
Explanation: Changing "might not" to "must" increases certainty about their receipt of the email.
4. It must be difficult to learn a new language as an adult.
Answer: It could be difficult to learn a new language as an adult.
Explanation: Changing "must" to "could" suggests that difficulty is one possible aspect of learning languages later in life.
5. She can’t have finished all that work in just one day.
Answer: She might not have finished all that work in just one day.
Explanation: Changing "can’t" to "might not" introduces doubt while suggesting it's unlikely she completed all the work quickly.
Statement of Purpose
Letter of Recommendation
Student Visa Application
Admission Essay Writing
Student Curriculum Vitae
Comments
(1319)