Welcome to your “Can” and “Must” lesson! In this topic we talk about:
• Modal verbs
• Constructing sentences with “Can”
• When do we use “Can”?
• Constructing sentences with “Must”
• When do we use “Must”?
• Short answers
Take the quizzes when you’re ready! If you’re having problems, use the comment box to contact our English Teachers.
Modal verbs
“Can” and “Must” are modal verbs. In the present, “Can” and “Must” are conjugated the same way, no matter the subject. In the 3rd person they never have an “+s”:
“I must work.”
“She must work.”
“They must work.”
Modal verbs are used to talk about a point of view, to say that something is possible, impossible, permitted or prohibited.
“You must take out the bin.”
Constructing sentences with “Can”
- Affirmative form:
subject + can + infinitive verb
“I can play the guitar.”
- Negative form:
subject + can’t + infinitive verb
“She can’t play the guitar.”
- Interogative form:
can + subject + infinitive verb
“Can they play the guitar?”
When do we use “Can”?
“Can” is used to talk about:
- an ability:
“I can play the trumpet.”
- an inibility:
“She can’t play the trumpet.”
- permission:
“I can go out tonight.”
- an impossiblility:
“They can’t go out tonight.”
Constructing sentences with “Must”
- Affirmative form:
subject + must + infinitive verb
“I must go to sleep.”
- Negative form:
subject + mustn’t + infinitive verb
“He mustn’t go to sleep.”
- Interrogative form:
must + subject + infinitive verb
“Must we go to sleep?”
When do we use “Must”?
“Must” is used to talk about:
- an obligation:
“I must go home early.”
- a prohibition:
“I mustn’t be late.”
Short answers
Short answers are formed:
“Yes + subject + modal verb” or “No + subject + modal verb + not.”:
“Can you dance?”
“Yes, I can.” / “No, I can’t.”“Must she go?”
“Yes, she must.” / “No, she mustn’t.”
