can / can't for ability
Ability and permission with can.
We use can + the base form of a verb to say that someone has the ability to do something, or to ask for or give permission. The base form is the simple dictionary form of the verb with no -s, -ing, or -ed ending. One very important rule is that can never changes, no matter who the subject is: I can, you can, he can, she can, it can, we can, they can — there is no 'cans' or 'caning'. To make a negative, we use can't (or cannot in more formal writing). To ask about ability or permission, we put can before the subject: Can you swim? — Yes, I can. / No, I can't. Short answers always use can or can't, never the main verb. We use can for both ability (permanent or present skill) and permission (asking or allowing). For example: 'Sara can play the guitar really well, but she can't read music yet — can she take lessons, Mum?'
Key terms
| Subject | Positive | Negative | Example |
|---|---|---|---|
| I | can | can't | I can swim. |
| you | can | can't | You can't run here. |
| he / she / it | can | can't | She can draw. He can't fly. |
| we | can | can't | We can sing. |
| they | can | can't | They can't drive. |
Note: 'can' NEVER changes. There is no 'cans' for he/she/it.
| Question form | Positive short answer | Negative short answer |
|---|---|---|
| Can I open the window? | Yes, you can. | No, you can't. |
| Can you swim? | Yes, I can. | No, I can't. |
| Can he/she/it fly? | Yes, he/she/it can. | No, he/she/it can't. |
| Can we use phones? | Yes, we can. | No, we can't. |
| Can they speak French? | Yes, they can. | No, they can't. |
To make a question, put 'Can' before the subject. Short answers use only 'can' or 'can't'.
| Use | Structure | Example |
|---|---|---|
| Ability (a skill) | can + base verb | She can play the piano. |
| Inability (no skill) | can't + base verb | He can't cook dinner. |
| Permission (asking) | Can + subject + base verb? | Can I go outside, please? |
| Permission (allowing) | You can + base verb. | Yes, you can sit here. |
| Permission (refusing) | You can't + base verb. | You can't use your phone in class. |
One word, two uses: ability and permission.
- 1Step 1: Think of the subject: Your sister → she
- 2Step 2: Put 'Can' at the start of the question: Can she ...
- 3Step 3: Add the base verb (no -s, no -to, no -ing): Can she speak English?
- 4Step 4: Give a short answer — use only 'can' or 'can't': Yes, she can. / No, she can't.
- 1Wrong sentence: He can rides a horse very fast.
- 2Problem 1: the verb after 'can' must be the base form: 'rides' has -s → remove -s → 'ride'
- 3Correct sentence: He can ride a horse very fast.
- 4Remember: can + BASE VERB only. Never: 'can rides', 'can riding', 'can to ride', 'cans ride'.
Do NOT write 'cans' or 'cans't'. 'can' is a modal verb and NEVER takes -s for any subject, including he, she, and it. Wrong: 'She cans swim.' Right: 'She can swim.'
Do NOT use 'do / don't / does / doesn't' with 'can'. Wrong: 'He doesn't can drive.' / 'Does she can sing?' Right: 'He can't drive.' / 'Can she sing?'
Do NOT add 'to' or '-ing' after 'can'. Wrong: 'We can to sing.' / 'We can singing.' Right: 'We can sing.' Always use the base form.
Short answers to 'Can...?' questions ONLY use 'can' or 'can't'. Never use 'do', 'does', 'am', 'is', or 'are'. Wrong: 'Yes, I do.' / 'Yes, she is.' Right: 'Yes, I can.' / 'Yes, she can.'
You can use 'Can I...?' to ask for permission as well as to ask about ability. For example: 'Can I open the window, please?' asks the teacher for permission.
Rules
- 1Use can + base verb to express ability: I can swim; She can draw; They can run fast.
- 2can never takes -s: say 'He can sing', NOT 'He cans sing'.
- 3Use can't (cannot) + base verb for inability or prohibition: He can't fly; We can't use phones in class.
- 4To ask about ability or permission, put can before the subject: Can you help me? Can I go outside?
- 5Short answers use can / can't only — never repeat the main verb: 'Yes, I can.' / 'No, she can't.'
Practice
10 easy · 10 medium · 10 hard
10 random questions per test