What Do We Mean by Deduction?
'Deduction' is the act of forming an opinion or making a guess based on available information. These opinions are formed by finding a logical relation between the order of events.
Here are some words that are used to make deductions in English.
Using 'Must'
You can use the modal verb 'must' when you are almost sure that something happens. You use 'must' with a reference to the present or future tense. Remember, after 'must' you have to use an infinitive without 'to.'
She looks wet, it
Can you hear the loud music? There
Using 'Have to'
The phrase 'have to' is used as the same meaning as the modal verb must. It has a similar function as well. You use 'have to' when you are almost 100% sure that something is true.
She
You
using 'have to' to talk about deductions
Using Could, Might, May
The modal verbs are used to talk about possibilities. This means at the time we are talking about the very event, we are not certain whether the thing is true or not.
She
Patrick
Using 'Cannot'
When it comes to 'deduction,' the modal verb 'can' in the negative form ('cannot') is exactly the opposite of the modal verb 'must.' Check out the examples.
He
It
Deduction: Past Tense
There are different structures to refer to the past tense. Usually, we use these phrases to express our opinion about a past event, that is formed by available information about the past.
- Could have
- Might have
- May Have
- Must have
- Had to
Using 'Must Have'
We can use the phrase 'must have' before 'past participles' to indicate we are almost sure that something has happened in the past. Remember in this case, we guess based on our personal knowledge about the event.
His eyes are red, he
Ian seems weird, she
Might Have, Could Have, May Have
The modal verbs 'may, might, could' can be added to the 'have + past participles' to talk about things that we are not certain about it.
Check out the examples for more clarifications.
Hanna
She
Using 'Had to'
The phrase 'had to' is used with the same meaning as 'must have.' This means we can use 'had to' to talk about things that we are sure are true about the past. Here is the key point: Use an infinitive without 'to' 'bare infinitive' after 'had to.'
Check out the examples to avoid confusion.
He
Alexandra
Review
Some verbs are used to talk about deduction. Here are the verbs: must, have to, cannot, could, may, might. To make past deductions you can use the verb phrase: could have, might have, may have, must have, had to
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Talking about Possibilities
There are different ways to talk about possibilities in English. Each way has its own function. We can also express our thoughts through possibilities.
Talking about Necessity
Some structures in English imply something that is not optional and there is a need to do them.
Giving Advice
'Giving advice' actually refers to expressing your opinion about a particular thing. In this case, you express something could happen in a better way.
Talking about Habits
Habits are things that we do regularly, from the past to the present time. Sometimes we can use some modals and semi-modals to refer to habits.
