Can & Could: The Friendly Helpers
Can opens doors: ability, permission and requests. Could is its polite older sibling — softer, more careful, and able to travel to the past.
Can & Could
One helper, many jobs
Can is the Swiss Army knife of English: it shows what you know how to do, what is allowed, and what you want to ask. Could does the same jobs, but softer — and it can also travel to the past.
Ability — you know how
what you can doI can swim
Permission — it is allowed
asking or giving the green lightCan I leave early?
Requests — a polite ask
asking someone to helpCan you help me?
Could — past or polite
ability in the past, or a softer askWhen I was six, I could run fast
⚠️ Can = the present helper. Could = the past one... or the politer question.
The Formula
Can + bare verb, always
The verb right after can never changes: no -s, no -ed, no to. Can itself never changes either — it works for every subject, all by itself.
Ican swimvery well
Shecan't drivea car
Can youhelpme?
Hecould readat age four
Common Mistakes
Four classic slips
Can is so friendly that learners keep trying to dress it up — with to, with -s, with do. It needs none of them. And for the past, forget did: could does the job.
I can to swim.
I can swim.
💡 After can, the verb is bare: no to.
He cans play guitar.
He can play guitar.
💡 Can never changes: no -s for he/she/it.
Can you to open the window?
Can you open the window?
💡 Question = can + subject + bare verb.
I can't went yesterday.
I couldn't go yesterday.
💡 The past is could + verb — no did, no -ed.
Quick Quiz
Test what you just learned
Three minutes, five questions — check what stuck. No essay questions, we promise.
I ___ swim very well.
💡 追加情報2 セクション
Who Does What
Two helpers, four jobs
Can and could share the work between them. Match each helper with its job.
⚠️ Same family, two manners: can gets straight to the point, could asks nicely.
Can's Three No's
What can refuses
Can is the most independent helper in English. It refuses every decoration — and it is right to.
No -s
he/she/it leaves can aloneShe can sing — not she cans
No to
bare verb right afterI can run — not I can to run
No do
questions and negatives build on can itselfCan you help? — not Do you can help?
⚠️ Three no's, one word: can does everything itself.