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Expressing possibility, probability, deduction and certainty using modal verbs.
Modal verbs and related expressions can show how possible, probable, or certain the speaker believes a situation to be.
Common forms include may, might, could, can, must, should, will, be likely to, and be certain to.
It may rain this afternoon.
Сегодня днём может пойти дождь.
"May" expresses possibility.
She might be at home now.
Она, возможно, сейчас дома.
"Might" expresses tentative possibility.
He must be tired after the long journey.
Он, должно быть, устал после долгого пути.
"Must" expresses strong deduction.
Prices are likely to increase.
Цены, вероятно, вырастут.
"Be likely to" expresses high probability.
May expresses a possibility that the speaker considers realistic or plausible.
For example, It may rain this afternoon and She may be at home.
It may rain this afternoon.
Сегодня днём может пойти дождь.
May expresses realistic possibility.
She may be at home.
Она, возможно, дома.
Present possibility.
We may go to the beach tomorrow.
Завтра мы, возможно, пойдём на пляж.
Future possibility.
Might expresses possibility and is often more tentative than may.
For example, We might go out tonight and He might be working late.
We might go out tonight.
Сегодня вечером мы, возможно, пойдём куда-нибудь.
Might is more tentative than may.
He might be working late.
Он, возможно, работает допоздна.
Present possibility.
They might not come to the party.
Они, возможно, не придут на вечеринку.
Negative possibility.
Could can express a possible situation or possible future event.
For example, It could rain later and She could be at the office.
It could rain later.
Позже может пойти дождь.
Could for possible future event.
She could be at the office.
Она, возможно, в офисе.
Present possibility.
He could be the new manager.
Он, возможно, новый менеджер.
Possible identity.
Can can express general or theoretical possibility rather than a prediction about one particular event.
For example, Accidents can happen and Winters can be very cold here.
Accidents can happen.
Несчастные случаи могут случаться.
General possibility, not about a specific event.
Winters can be very cold here.
Зимы здесь могут быть очень холодными.
Theoretical possibility.
Smoking can cause health problems.
Курение может вызывать проблемы со здоровьем.
General truth.
May, might, and could can all express possibility, with differences often involving tentativeness, context, or speaker perspective rather than a fixed probability scale.
For example, It may rain, It might rain, and It could rain can all describe a possible future event.
It may rain.
Может пойти дождь.
May: realistic possibility.
It might rain.
Возможно, пойдёт дождь.
Might: more tentative.
It could rain.
Может быть, пойдёт дождь.
Could: also possible; often interchangeable.
Must can express a strong logical conclusion based on available evidence.
For example, The lights are on, so they must be home.
The lights are on, so they must be home.
Свет горит, значит, они, должно быть, дома.
Logical conclusion from evidence.
She has been working all day; she must be exhausted.
Она работала весь день; она, должно быть, измотана.
Strong deduction.
This must be the right address.
Это, должно быть, правильный адрес.
Conclusion based on evidence.
Cannot or can't can express that a situation is logically impossible or extremely unlikely based on evidence.
For example, That cannot be true and She can't be serious.
That cannot be true.
Это не может быть правдой.
Logical impossibility.
She can't be serious.
Она не может говорить это серьёзно.
Strong disbelief.
They can't have arrived already; it's too early.
Они не могли уже приехать; ещё слишком рано.
Past deduction with can't have.
Should can express an expectation that something is likely to happen or be true.
For example, The train should arrive soon and She should be home by now.
The train should arrive soon.
Поезд должен скоро прибыть.
Expectation based on schedule.
She should be home by now.
Она, должно быть, уже дома.
Reasonable expectation.
This medicine should help with the pain.
Это лекарство, вероятно, поможет от боли.
Expected effectiveness.
Will can express a confident prediction or expectation about a future event.
For example, She will probably arrive soon and That will be John at the door.
She will probably arrive soon.
Она, вероятно, скоро приедет.
Confident prediction.
That will be John at the door.
Это, наверное, Джон у двери.
Deduction/expectation.
You will feel better after a rest.
Тебе станет лучше после отдыха.
Confident future prediction.
Be likely to expresses a high or moderate probability that something will happen or be true.
For example, Prices are likely to increase and He is likely to agree.
Prices are likely to increase.
Цены, вероятно, вырастут.
High probability.
He is likely to agree to the proposal.
Он, вероятно, согласится на это предложение.
High probability.
It is likely to rain later.
Позже, вероятно, пойдёт дождь.
Probability.
Be unlikely to expresses a low probability that something will happen or be true.
For example, They are unlikely to arrive before noon.
They are unlikely to arrive before noon.
Они вряд ли приедут до полудня.
Low probability.
She is unlikely to accept the offer.
Она вряд ли примет это предложение.
Low probability.
It is unlikely to snow in May.
В мае вряд ли пойдёт снег.
Low probability.
Be certain to expresses a very high degree of confidence that something will happen or be true.
For example, She is certain to succeed.
She is certain to succeed.
Она наверняка добьётся успеха.
Very high confidence.
The plan is certain to fail.
План наверняка провалится.
High confidence in outcome.
He is certain to be late again.
Он наверняка снова опоздает.
Strong expectation.
Probability can also be expressed with adverbs such as probably, certainly, definitely, perhaps, maybe, and possibly.
These adverbs often combine with modal verbs and other future expressions.
She will probably come to the party.
Она, вероятно, придёт на вечеринку.
Probably expresses moderate-high probability.
Maybe he is busy.
Может быть, он занят.
Maybe for possibility.
Perhaps we should leave now.
Возможно, нам пора уходить.
Perhaps for suggestion/possibility.
Probability adverbs have characteristic positions that can differ according to the verb structure.
For example, She will probably come, She has probably left, and She is probably at home.
She will probably come.
Она, вероятно, придёт.
Probably after will.
She has probably left.
Она, вероятно, ушла.
Probably after have/has.
She is probably at home.
Она, вероятно, дома.
Probably after be.
Modal verbs can express uncertainty about a situation that is true or happening now.
For example, She may be tired, They might be waiting outside, and He could be at work.
She may be tired.
Она, возможно, устала.
Present possibility with may.
They might be waiting outside.
Они, возможно, ждут снаружи.
Present ongoing possibility.
He could be at work.
Он, возможно, на работе.
Present possibility.
Modal verbs can express uncertainty about future events.
For example, We may go tomorrow, It might snow tonight, and They could arrive late.
We may go tomorrow.
Завтра мы, возможно, пойдём.
Future possibility with may.
It might snow tonight.
Сегодня ночью, возможно, пойдёт снег.
Future possibility with might.
They could arrive late.
Они могут опоздать.
Future possibility with could.
Modal perfect forms can express uncertainty or deduction about past events.
For example, She may have forgotten, They might have missed the train, and He could have taken the wrong road.
She may have forgotten.
Она, возможно, забыла.
Past possibility with may have.
They might have missed the train.
Они, возможно, опоздали на поезд.
Past possibility with might have.
He could have taken the wrong road.
Он, возможно, поехал не по той дороге.
Past possibility with could have.
Must have + past participle expresses a strong conclusion about something that happened in the past.
For example, He must have forgotten the meeting and They must have left already.
He must have forgotten the meeting.
Он, должно быть, забыл о встрече.
Strong past deduction.
They must have left already.
Они, должно быть, уже ушли.
Logical conclusion about past.
She must have been very upset.
Она, должно быть, была очень расстроена.
Past state deduction.
Cannot have + past participle expresses that a past event is considered impossible or extremely unlikely.
For example, She cannot have forgotten; I reminded her yesterday.
She cannot have forgotten; I reminded her yesterday.
Она не могла забыть; я напомнил ей вчера.
Impossible past event.
They can't have arrived yet; the flight was delayed.
Они не могли уже приехать; рейс задержали.
Past impossibility.
He cannot have said that.
Он не мог такого сказать.
Strong disbelief about past.
May have and might have express possible past events or states.
For example, She may have missed the bus and They might have misunderstood the question.
She may have missed the bus.
Она, возможно, опоздала на автобус.
Past possibility (may have).
They might have misunderstood the question.
Они, возможно, неправильно поняли вопрос.
Past possibility (might have).
He may not have received the email.
Он, возможно, не получил письмо.
Negative past possibility.
Could have + past participle can describe a possible explanation for a past situation.
For example, He could have taken a different route.
He could have taken a different route.
Он мог поехать другой дорогой.
Possible explanation for past event.
She could have been delayed by traffic.
Её могли задержать пробки.
Possible cause.
They could have forgotten the appointment.
Они могли забыть о встрече.
Past possibility.
Possibility and probability are related but not identical concepts.
A statement can be possible without being particularly probable. Context and the chosen modal or expression communicate the speaker's degree of confidence.
It may be sunny tomorrow.
Завтра, возможно, будет солнечно.
Possibility: could happen, but not necessarily likely.
It is likely to be sunny tomorrow.
Завтра, вероятно, будет солнечно.
Probability: more than 50% chance.
It will be sunny tomorrow.
Завтра будет солнечно.
Certainty/prediction.
Different expressions can communicate different degrees of confidence, although their interpretation depends on context.
Expressions such as might, may, could, should, will, must, and be certain to can place a statement at different points on a continuum of confidence.
She might be at home.
Она, возможно, дома.
Weak possibility.
She may be at home.
Она, возможно, дома.
Slightly stronger than might.
She could be at home.
Она может быть дома.
Another moderate possibility.
She should be at home by now.
Она, должно быть, уже дома.
Higher expectation.
She must be at home.
Она, должно быть, дома.
Strong deduction.
Modal deduction uses evidence to indicate how strongly the speaker believes a conclusion follows from the available facts.
For example, The ground is wet, so it must have rained and The ground is dry, so it cannot have rained recently.
The ground is wet, so it must have rained.
Земля мокрая, значит, шёл дождь.
Deduction from evidence.
The ground is dry, so it cannot have rained recently.
Земля сухая, значит, дождя недавно не было.
Negative deduction.
Her car is outside, so she may be at home.
Её машина снаружи, так что она, возможно, дома.
Possible conclusion.
Modal verbs can soften statements by presenting them as possibilities rather than facts.
For example, This may be the reason is less direct than This is the reason.
This may be the reason.
Это, возможно, причина.
Softening a claim.
This is the reason.
Это причина.
Direct factual statement.
That might not be correct.
Это, возможно, неверно.
Polite disagreement.
Formal writing frequently uses modal verbs and probability expressions to avoid presenting uncertain claims as absolute facts.
For example, The results may indicate, This could suggest, and The treatment is likely to improve outcomes.
The results may indicate a trend.
Результаты могут указывать на тенденцию.
Cautious academic statement.
This could suggest a correlation.
Это может указывать на корреляцию.
Tentative academic language.
The treatment is likely to improve outcomes.
Лечение, вероятно, улучшит результаты.
Probability in formal writing.
Choose modal verbs and probability expressions according to the intended degree of possibility, probability, or certainty.
Common mistakes include confusing must for obligation with must for deduction, using can for a specific uncertain future event, confusing may not with must not, and using modal perfect forms incorrectly.
It can rain later.
Позже может пойти дождь.
For a specific future possibility, "may/might/could" is more natural; "can" is for general possibility.
She must be at home?
Она, должно быть, дома?
Question with must for deduction is unusual; use "Could she be at home?" or "Is she likely to be at home?"
They can't be tired; they slept all day.
Они не могут быть уставшими; они спали весь день.
Correct use of can't for deduction.
She might have to be at home.
Она, возможно, должна быть дома.
Incorrect: "might have to" means obligation, not possibility. Use "She might be at home."