Introduction
Modals of deduction and speculation are also called modals of probability. We find them when we want to make a guess about something.
Different modals can be used depending on how sure we are about a situation.
Form
The most commonly used modals of probability are can, could, may and must.
They have different structures.
Can/Can’t
The affirmative form is:
Can + bare infinitive.
The negative form is:
Can’t + bare infinitive.
Could/couldn’t
The affirmative form is:
Could + bare infinitive.
The negative form is:
Could not + bare infinitive.
May/may not
The affirmative form is:
May + bare infinitive.
The negative form is:
May not + bare infinitive.
Might/might not
The affirmative form is:
Might + bare infinitive.
The negative form is:
Might not + bare infinitive.
Must
The affirmative form is:
Must + bare infinitive.
The negative form is:
Must + not + bare infinitive.
Should/should not
The affirmative form is:
Should + bare infinitive.
The negative form is:
Should + not + bare infinitive.
Example
- He can’t go to school because there is a heavy snowfall outside.
- She couldn’t paint this wall with watercolours.
- Environmental problems and natural disasters may create problems for people.
- There might be traffic on the main road because of the festival.
- Nuclear energy must be harmful for the environment.
- Thunders and lightnings should make noise.
Use
We use modals of probability when we talk about a present situation.
We use:
- can: to talk about something that happens sometimes, something possible;
- could, may/might: for probabilities and predictions;
- must: when we are sure about something;
- should: to make a guess about something that is likely to happen.
Summary
Modals of probability, also called modals of deduction and speculation, are used when we want to make a guess about something. Different modals of probability can be used depending on how sure we are about a present situation.
The most commonly used modals of probability are can, could, may and must.
We use:
- can/ can’t followed by a verb in the bare infinitive form, to talk about something that happens sometimes, something possible;
- could/couldn’t, may/may not/might/might not followed by a verb in the bare infinitive form, to talk about probabilities and predictions;
- must is followed by a verb in the bare infinitive form, when we are sure about something;
- should/should not followed by a verb in the bare infinitive form, to make a guess about something that is likely to happen.
For example:
— “I may not be on time tomorrow for dinner, because we will have a meeting at work.” = I am predicting that I will be late for dinner tomorrow.
— “He must be at work now.” = I am sure that he is at work now.
Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.