What Could and Couldn't Are
Could is the past form of can. It says a person knew how to do a thing, or was able to do it, back then. Couldn't says the opposite: they did not know how, or one time they tried and it did not work out.
ABLE TO, BACK THENPast ability
Now: can. Back then: could.
I could read when I was four.
I learned to read early.
NOT ABLE TOOne particular time
She couldn't sleep last night. The neighbours were very loud.
She tried to sleep, but it did not work.
For ability in the past, can changes to could.
TRY IT
- Question 1
"When I was five, I write my name."
- Question 2
"The shop was closed, so we buy any milk."
The four shapes
POSITIVE
ScouldV
My dad could fix cars.
Every subject takes could. The verb after it stays bare.
NEGATIVE
Scouldn'tV
We couldn't find the hotel.
Couldn't is the everyday form; could not is the full one.
QUESTION
CouldSV?
Could your grandfather speak French?
Could goes in front of the subject. There is no did.
SHORT ANSWER
Yes / No,Scould / couldn't
Yes, he could. — No, he couldn't.
Repeat could, not the main verb.
CAN → COULD
- cancould
- can'tcouldn't
Could already carries the past, like did in didn't go. So the verb after it stays in its base form: could swim, not could swam.
Could is pronounced /kʊd/ — the l is silent.
TRY IT
- Question 1
"My grandmother could three languages."
- Question 2
"I open the door — I didn't have my key."
- Question 3
"Could you swim when you were ten? — No, I ."
When to use it
A skill you had
My uncle could play the guitar when he was young.
A skill a person had at a time that is over.
Signal words: when I was young · as a child · at the age of five
Not able to, that time
We couldn't hear the teacher at the back of the room.
One time a person tried and it did not work.
Signal words: couldn't find · couldn't sleep · couldn't open
Asking about the past
Could you cook when you were a student?
Answer with Yes, I could or No, I couldn't.
Signal words: Could you …? · Could she …? · Could they …?
Asking politely
Could you close the door, please?
This question is about now, not the past.
Signal words: Could you …, please? · Could I …?
Past could vs. polite Could you…?
Both kinds of question start with Could. One asks about back then. The other asks the listener to do a thing right now.
| COULD · PAST | COULD YOU…? · POLITE | |
|---|---|---|
| Meaning | Did you know how to, back then? | Can you do this for me, right now? |
| Example | Could you use chopsticks when you were six? | Could you help me with this bag? |
| Signals | when I was …, last year, then | please |
| Replies | Yes, I could. · No, I couldn't. | Sure. · Of course. · Sorry, I can't. |
To say no to a request, say Sorry, I can't, because you cannot help right now.
TRY IT
- Question 1
"Could you tell the time when you were five? — "
- Question 2
"Could you call me back later? — Sorry, I . I'm in a meeting all afternoon."
Common mistakes
Incorrect:When I was young, I can run fast.
Correct:When I was young, I could run fast.
The sentence is about a time that is over, so can changes to could.
Incorrect:My sister could to draw very well.
Correct:My sister could draw very well.
A bare verb follows could, with no to — exactly as after can.
Incorrect:Did you could speak English last year?
Correct:Could you speak English last year?
Could makes its own question by moving to the front. It does not need did.
Incorrect:I didn't could find a taxi.
Correct:I couldn't find a taxi.
Could makes its own negative with n't. Adding didn't marks the past twice.
Incorrect:She couldn't answered the question.
Correct:She couldn't answer the question.
Couldn't already carries the past, so the verb after it stays in its base form.
Incorrect:I could pass the exam last week.
Correct:I passed the exam last week.
For one success at one time, use the past simple. Could is for a skill you had over a longer time.
Incorrect:Could you open the window? — Sorry, I couldn't.
Correct:Could you open the window? — Sorry, I can't.
Could you…? here is a polite request about now, so the refusal uses can't.
Quick check · 8 questions
Choose the correct word:
My little brother could walk when he was ten months old.
- A. could — Correct
- B. can
- C. coulds
Answer: A. could
When he was ten months old is in the past, so the word is could. Like can, could never takes an -s.
Choose the correct form:
Tuấn could play chess at the age of four.
- A. play — Correct
- B. to play
- C. played
Answer: A. play
Could already carries the past, so the verb after it stays in its base form: no to, and no past form either.
Choose the correct form:
It was very dark, so we couldn't see the path.
- A. couldn't — Correct
- B. didn't could
- C. can't
Answer: A. couldn't
Could makes its own negative with n't, with no did. "Can't" is present, so it does not fit it was.
Choose the word that starts the question:
Could your parents use a computer twenty years ago?
- A. Could — Correct
- B. Did could
- C. Can
Answer: A. Could
Like can, could goes in front of the subject to make a question, with no did. Twenty years ago is the past, so can does not fit.
Choose the correct short answer:
Could Minh drive last year? — No, he couldn't.
- A. couldn't — Correct
- B. didn't
- C. can't
Answer: A. couldn't
A short answer repeats the word the question started with. This one starts with Could, so the answer is No, he couldn't.
Choose the correct form:
Sorry, I couldn't understand what she said.
- A. understand — Correct
- B. understood
- C. understanding
Answer: A. understand
Couldn't already says past, so understand does not change to understood. It is the same after didn't.
A friend is asking you for help right now. Choose the correct reply:
Could you give me a lift to the station? — Sorry, I can't. My car is at the garage.
- A. can't — Correct
- B. couldn't
Answer: A. can't
Here Could you…? is a polite way to ask. It is not about the past. You cannot help right now, so the reply is Sorry, I can't.
Choose the correct form:
I couldn't catch the bus this morning, so I was late for work.
- A. couldn't catch — Correct
- B. can't catch
- C. couldn't caught
Answer: A. couldn't catch
This morning is past, so can't is wrong. After couldn't the verb stays in its base form: catch, not caught.
See whether it really stuck.
Start the quiz · 12 questions