63 Deductions - Must/Can’t
Modals
Must and Can’t are modal verbs that can be used even to express deductions.
There are differences in meaning between two modal verbs.
Below is the structure of these verbs when used to express deduction:
Affirmative
The Affirmative form is as follows:
Subject + must + verb.
Negative
The Negative form is as follows:
Subject + cannot + verb.
- She’s shivering. She must be cold!
- Your forehead is so hot! You must have a fever!
- He is late, he can’t catch the plane.
- They don’t answer the phone. They can’t be at home.
Must and Can’t are modal verbs that can be used for deductions if we have strong evidence.
We use Must in Affirmative Clauses when we are sure about something and usually have enough information or strong evidence.
We use Can’t in Negative Clauses when we believe that something is not true or impossible.
The difference between the two verbs is that Must cannot express certainty in Negative clauses and on the other side Can’t is just used to express certainty in Negative clauses.
We can use the modal verbs Must and Can’t to deduce certain things due to strong evidence. Must is used in Affirmative clauses, when we are sure about something, whereas Can’t is used in Negative clauses, when we believe that something is not true or impossible.
Therefore, the structure for the Must and Can’t are as follows:
- Affirmative: Subject + must + verb;
- Negative: Subject + can + not + verb.
For example:
— “He has two private jets, he must be rich.” = We are sure that he is rich, we have enough evidence to prove it.
— “The show starts in 5 minutes. They can’t be on time.” = It is impossible for them to be on time.
Let’s revise this content within the [Form] section. Take a look at the [Example] section that shows its use within a context.