Can / Could
Formula
Examples
Usage
- •Can: present ability, permission, or possibility
- •Could: past ability, polite requests, or weaker possibility
- •Could: more polite than "can" for requests
More Examples
I can run 10 km without stopping.
What you can do now
She could read when she was four.
What you could do before
Could you pass me the salt, please?
A polite way to ask for something
It could rain tomorrow.
Something that might happen, you are not sure
Can I use your phone?
Asking for permission
Common Mistakes
- ✗"Can" never takes "to": "I can to swim" is wrong — use "I can swim".
- ✗Don't use "could" for a single specific past event: say "I managed to open the door" not "I could open the door" in that context.
Tips
- ✓"Could" is the past tense of "can" and also a polite alternative in requests.
- ✓For ability in the past (success on one occasion), use "was/were able to" instead of "could".
Advanced Notes
The "could for single past achievement" trap is one of the subtlest modal errors: "could" implies general past ability, not a specific success. "I could finally open the jar" sounds odd to native ears — "I managed to open it" or "I was able to open it" is correct. In requests, "could" is more tentative than "can" and significantly more tentative than "would" — the hierarchy "can < could < would" reflects increasing formality and politeness. "Can't" also functions as logical deduction: "She can't be at home — I just saw her leave."
Compare With
Other A2 Topics
Present Continuous
Used for actions happening now or temporary situations
Past Continuous
Used for interrupted past actions or background description
Future with Going to
Used for decided plans and evidence-based predictions
Comparatives and Superlatives
Used for comparing qualities between items or identifying the extreme
Prepositions of Time and Place
Used for time and location relationships using in, on, at
Adverbs of Frequency
Used for stating how often something happens
Possessive 's
Used for showing ownership or association using apostrophe + s
Quantifiers: Some, Any, Much, Many, A Lot Of
Used for unspecified quantities in positive, negative, and question contexts
Basic Linkers: And, But, Or, Because, So
Used for connecting ideas within or between sentences
Object Pronouns: Me, You, Him, Her, It, Us, Them
Used for replacing nouns as the object of a verb or preposition