Could

After could, use the base verb without to: cook, read, write, be. Do not add -s for he/she/it or change the main verb to a past form.

Could together with the context already conveys the past meaning. Could itself does not change according to the subject either.

Form the negative with couldn't or full could not. Do not add didn't. The full form is suitable, for example, for emphasis or a more formal account.

Couldn't can refer either to a general inability or to a particular past failure. Do not extend the restriction on affirmative one-off success to negative sentences.

In a direct question, could comes before the subject. For a wh-question, add what, how, or another question word first. Did is unnecessary.

A short answer repeats could or couldn't/could not: Yes, I could. No, I couldn't. A past-time frame helps distinguish a question about ability from a polite request.

Could is natural for a general past skill. To report that a particular action actually succeeded on one occasion, we usually choose was/were able to or managed to. Managed to often emphasises effort or difficulty.

This is not a rule that any date prohibits could. Identify whether the meaning is general ability, an actual achievement, inability, or perception. Do not call was able to incorrect merely because the sentence describes a general skill.

With verbs of perception and mental activity, such as see, hear, feel, remember, and understand, could can naturally refer to one particular past moment.

Do not mechanically correct could see the sea last night simply because of last night. The negatives couldn't see, couldn't hear, and couldn't understand are equally natural.

Could does not always express past ability. Could you help me, please? is a request; Could I use this chair? asks permission; It could rain tomorrow expresses future possibility. A skill interpretation requires the right meaning, not simply the word could.

In your own account, name the past period, choose an action, and decide whether the ability existed. If the other person has already established the time, you do not need to repeat it. Facts may be invented for practice answers.

After Could you, name the action you want the addressee to perform: send, open, repeat, wait. Include the object, recipient and time as needed to make the request clear.

Can you…? is also a common and often perfectly polite request. Could you…? usually sounds softer or less direct; the difference concerns appropriateness and register, not whether can is grammatical.

Could I…? asks whether the speaker may perform an action. Could we…? asks permission for a group the speaker belongs to. I/we and you therefore change both the person acting and the communicative purpose.

May I…? also correctly asks permission and often sounds more formal. If an exercise specifically asks for could, May I may be grammatical but fail to meet the exercise's aim.

In a direct question, could comes before the subject. Do, does or did is not needed. After the subject, use the base form of the verb without to, -s, -ing or a past-tense form.

Could does not change for person: Could I ask…? Could she help…? Could you wait…? The modal verb already carries the question's grammatical structure.

Please often comes at the end of a request or between the subject and main verb. Both positions are natural: Could you repeat that, please? and Could you please repeat that?

Could you repeat that? without please is grammatical too and may be appropriate. Do not reject such an answer unless the stated task requires you to convey an explicit 'please' or use all the supplied words.

Would you + base verb can also be a polite request. The separate pattern Would you mind requires -ing: Would you mind closing the door? Do not falsely label the correct Would you close the door? as an error.

Could you not + base verb asks someone not to do something: Could you not call before nine? This form can sound firm or irritated, so it needs a clear reason and an appropriate context.

A natural way to agree to Could you…? is Sure, Of course or Yes, I can; you can refuse with Sorry, I can't and a brief reason. Yes, I could often sounds like an answer about ability rather than willingness to carry out a present request.

Natural ways to grant permission after Could I…? include Of course, Certainly and Yes, you can. In a neutral modern response, could is not mechanically repeated to grant or refuse permission.

In your own answer, preserve the action, participants, object, time limit and polarity. The model is one natural version, not a list of every possible correct reply.

In a suggestion, could shows that the action is one possible solution. We could… often concerns a shared plan, You could… offers the other person an option, and I could… presents something the speaker is willing or able to do. After could, always use the base form without to.

Could usually leaves more room for choice than a command. Should can also give advice, but it often sounds like a recommendation that the speaker considers good. This does not mean that should is always harsh or that could is always better: appropriateness depends on the situation and intonation.

Maybe, perhaps, or the construction could always can further emphasize that this is only an option: Maybe we could meet online. You could always ask at reception.

Could can say that a specific state now or an event in the future is possible, but the speaker is not certain: Nina could be at home. It could rain tonight. This is an assumption, not a fact or a promise.

May, might, and could often express the same basic idea of uncertain possibility. The difference between them may depend on style, context, and the speaker; do not assign fixed percentages to them or call a grammatical alternative an error. May often sounds more formal.

Can often describes general possibility or something that sometimes happens: Roads can be icy in winter. For a specific uncertain assumption, may, might, or could are natural: This road could be icy tonight.

Could does not change according to person: I could, she could, they could. The next verb has the base form: could go, could be, could arrive. Do not add to, -s, or a past form.

In a question, could comes before the subject: Could we try another café? Could it be the battery? Do/does/did are not needed. The question Could we…? often suggests a shared option; Could it…? can check an assumption.

Could not/couldn't exists, but it is not a simple mirror image of uncertain could. Couldn't often means impossibility or inability. When you are not sure that something will happen, it is natural to say may not/might not or to express a possible negative state: The road could be closed.

We could leave earlier after a conversation about traffic — a suggestion. We could be late after a report about traffic — a possible result. The words are similar, but their roles are different: in the first sentence, people choose an action; in the second, they assess an unknown future.

Could you take the earlier train? may be a polite request or a suggestion, depending on the situation and intonation. For teaching clarity, add context: If the 8:00 train is full, you could take the 8:30 train — an obvious option; I need you here by nine. Could you take the earlier train? — a request.

Could I…? often asks for permission, while I could… in an affirmative statement can suggest the speaker’s own action. I could call the hotel, if you like — an offer of help; Could I call from here? — a request for permission.

Natural responses to a suggestion include Good idea, That could work, Maybe, or another option. The other person may accept, reject, or change the idea: We could walk. — Good idea. / Maybe, but the bags are heavy.

A statement about possibility can prompt checking, a plan, or a precaution: The road could be closed. — Let's check the map. This response does not confirm that the road is actually closed.

In a productive response, preserve the participants, time, subject, polarity, and degree of certainty. Do not silently change could into will or turn a possible event into a fact.

Could also describes general ability in the past, a polite request, and a request for permission. These meanings are studied separately. In this material, they are included so that you do not call every could a suggestion or a possibility.

For general past ability, could is natural: I could swim when I was six. When referring to one specific successful event, was/were able to or managed to is usually needed: The door was locked, but we managed to open it. This is another boundary, not a third core meaning of this rule.

Could have + V3 can express past possibility, an unused opportunity, or criticism. Here, focus on could + the base form for present or future possibility; the meanings of could have are studied separately.

Intonation can change the force of a question or suggestion, but a text-based practice tool does not measure it. Therefore, closed exercises provide enough written context and do not present one possible intonation as the only one.