Figure out which situation you're in, then match it to one can sentence. Ability now: She can swim well. Asking someone for something: Can you pass the salt? (Could sounds more polite.) Permission and possibility cases follow below.
Pick the situation you're in, then finish the sentence: She ___ swim well. If you chose can, correct: it fits ability. She can driving would be wrong. The cases below show which wording each situation calls for.
If someone has the skill right now, use can plus the plain verb. Alan can swim well. The verb never changes for he or she, and it takes no -ing or -ed: She can drives and She can driving are both wrong.
If you're pointing to a future possibility, can still works. We can meet on Friday. Contrast it with a real past event: say I couldn't come yesterday or I wasn't able to come, not I can't come yesterday.
If you're stating something that happens sometimes, can marks a general possibility. Winters here can be very cold. Compare could or may in the same sentence; they sound more tentative, so reach for can when the possibility is a normal, expected one.
In casual situations, a question with can asks permission naturally. Can I leave early today? And to grant it, just answer with can too: Yes, you can.
At work or with someone formal, may sounds more formal and polite. May I borrow your stapler? is more formal than Can I borrow your stapler?, though both are accepted in everyday speech. Note that may is only used with I and we. So the ladder runs like this: ask with can in casual settings, use could for extra politeness, and may for the most formal moments. When you grant permission, only can and may fit, so answer Yes, you can. or Yes, you may. Could doesn't work there; it isn't used to give permission, so Yes, you could. isn't the way to grant it. If you asked with could, a natural answer is still Yes, you can. Ask with could for politeness, but don't echo it back in the reply. Keep the granting answer on can (or may).
when to use can
Situational usage guide for choosing can
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can in past
This guide answers the question directly: use **could** when you're talking about a general ability you had in the past, and use **was/were able to** or **managed to** when you're describing one specific success, one completed event. The distinction comes out most clearly in the examples, which are grouped by the reader's situation. For general ability, **could** fits on its own: *When I lived by the sea, I could swim every day.* For a single completed success, **could** normally doesn't work, and you need the other forms: *I was able to win the race yesterday* (not ~~I could win the race yesterday~~), or *Only a few students managed to pass the exam.* The guide folds the boundary on sense verbs into the relevant case: verbs like *see*, *hear*, *understand* keep **could** even for a specific moment, because they describe perception rather than an achievement.
usage
when we can use would
usage-guide-when-to-use-would,
usage
when would is used
**When would fits your sentence** Reach for **would** when your sentence steps away from what's real or direct right now. That covers four everyday situations, and each one has its own tell. **Imagined or unreal situations.** If you're talking about something that hasn't happened or isn't true, would marks it as hypothetical. > *If I had more time, I would learn the guitar.* You don't have more time, so would signals that the guitar is a wish, not a plan. **Polite requests.** When you ask someone to do something, would softens the ask. Compare: > *Would you make dinner tonight?* > *Will you make dinner tonight?* Both work, but the first sounds gentler and less demanding. For an even more careful ask, there's a common set phrase: > *Would you mind closing the window?* **Past routines.** When you look back on habits you used to have, would works like *used to*, but only for repeated actions. > *Every summer, we would drive to the lake.* One important limit here: would doesn't describe past states. You can say *we would visit the lake*, but not *we would live in that town* for a one-time situation. Use *used to live* instead. **Reported speech.** If you're passing on what someone said and their original words used *will*, it becomes would in your report. > Direct: *"I will call you tomorrow."* > Reported: *She said she would call me the next day.* **A quick way to decide** Ask yourself: is the situation real and happening now, or is it imagined, softened, or reported? Real and direct takes *will*: *I will be there at six.* Anything imagined, polite, habitual in the past, or reported takes would. That single distance from reality is the whole reason would shows up where it does. --- **Try it:** Your coworker is carrying a heavy box, and you want to offer help in the friendliest way. Which sentence fits best? - A) *Will you help you with that?* - B) *Would you like some help with that?* Good answer: B. *Would you like...* is a natural, polite offer, and it invites the other person to say yes comfortably. Wrong answer: A. This sentence mixes up pronouns and *will* sounds blunt for an offer. The friendly version is *Would you like some help with that?* --- Keep exploring this distinction with the guide to **will vs. would** for more side-by-side examples.
comparison
can vs will
Compact can vs will choice guide with paired examples and one boundary
usage
can i have some
Situational usage guide for 'Can I have some' when asking for a portion
usage
can i play too read aloud
Situational usage guide: when and how to use the phrase 'Can I play too?'