Why does English use a past tense to talk about now?

Because the past form is being used as a mood marker, not as a time marker. Moving one step back from the time you mean is how English signals that the situation is hypothetical. Many European languages use a subjunctive instead; English mostly borrows past morphology for the same job.

What is the difference between If I knew and If I had known?

If I knew is about now: I do not know. If I had known is about then: I did not know. Match the result to the same time: I would wait versus I would have waited. Mixing them is only right when the times really differ: If I had packed the visor, I would be dry now.

Should I write If I was or If I were?

Were is the traditional written form with every subject in unreal present clauses: If I were you, If it were quieter. Was is common after I and he/she/it in speech. After wish, were is still the safer choice in writing: I wish I were on the jetty.

Can I use would in the if-clause?

Not in the standard pattern for unreal present or past. If I would know and If I would have known are the usual learner errors. The exception is polite willingness: If you would wait on the jetty, I'll fetch the visor, where would means be willing to, not a hypothesis.

English grammar · Intermediate

Unreal Tenses: Past Forms for Imagined Present and Past

Written by Eleanor Whitfield, Lead English Curriculum Editor · Reviewed September 2026

Unreal tenses are past forms used to talk about situations that are imagined, hypothetical, or contrary to fact. A past simple after if, wish, or I'd rather points at an unreal present (If the lighthouse had a lift: it does not). A past perfect points at an unreal past (If the lighthouse had had a lift: it did not). The result clause takes would, could, or might, plus a bare verb for now or have plus a past participle for then.

If the lighthouse had a lift, we would take the crates up in one trip.

past simple after if for a present that is not true; would in the result

What it is

English borrows a tense from further back in time to mark that a situation is not real. The past simple stands for an imagined now (If I lived in the lock cottage: I do not). The past perfect stands for an imagined then (If I had lived in the lock cottage: I did not). Nothing in those if-clauses happened, and that is the point. The same backshift appears after wish, if only, I'd rather, it's time, and as if. Would in the result clause is not a future marker here; it is the modal of the imagined outcome.

If the quarry were quieter, I would sleep. (It is not quieter; this is about now.) If the quarry had been quieter, I would have slept. (It was not; this is about last night.)

How to spot it

Look for if, wish, if only, I'd rather, it's time, or as if, then a past form that does not mean past time. If the sentence is about now but the verb is past, or about then but the verb is past perfect, you are in unreal territory. Would, could, or might in the other clause confirms it.

If I knew the millrace, I would not take the barge out. (knew is unreal present)
If I had known the millrace, I would not have taken the barge out. (had known is unreal past)
I wish the foundry closed at dusk. (wish plus past simple about now)
I'd rather we waited on the jetty. (would rather plus past simple, a preference now)

Were is the traditional form of be in unreal present clauses with every subject (If I were, If it were). Was is common in speech (If I was). Both are heard; were is the safer written choice after if and wish.

Unreal Tenses Quick Reference

Real time versus the form English uses

Meaning	Form after if / wish	Result clause	Example
Imagined present or future	past simple	would / could / might + bare verb	If it rained, we would stay in.
Imagined past	past perfect	would / could / might have + past participle	If it had rained, we would have stayed in.
Present wish	wish + past simple	(no result clause needed)	I wish it rained less.
Past wish	wish + past perfect	(no result clause needed)	I wish it had rained less.
Mixed: past cause, present result	if + past perfect	would + bare verb	If I had packed the visor, I would be dry now.

Common Unreal Tenses Examples in English

The same logic, applied to the places learners meet it:

Imagined Present

If the lighthouse had a lift, we would take the crates up in one trip.: it does not have a lift
If I were the lock-keeper, I would keep a spare visor.: I am not the lock-keeper
If we lived nearer the tram depot, we would not need the barge.: we do not live nearer
Suppose the millrace froze. We would walk across.: suppose plus past, still unreal now

This is the second-conditional pattern. The past form does not place the situation in yesterday; it marks it as untrue.

Imagined Past

If the quarry had been open, we would have fetched the stone.: it was closed; we did not fetch it
If she had radioed, the barge would have waited.: she did not radio
If we had taken the tram, we would not have missed the jetty.: we did not take the tram
Had the winch jammed, we would have used the spare.: inverted if, same unreal past

This is the third-conditional pattern. The detail page for that structure sits next door; this page is the tense logic under it.

Wish and If Only

I wish the orchard had a well.: it does not; past simple for now
If only we had checked the cistern.: we did not; past perfect for then
I wish the foundry would go quiet after ten.: a change of someone else's habit
If only the harbour wall were higher.: were for unreal present be

Wish plus would is about behaviour you want to change, not about a state. I wish I would is rarely natural; I wish I could is.

Mixed Unreal

If I had packed the visor, I would be dry now.: past condition, present result
If the lock cottage were on the bus route, we would have moved there years ago.: present condition, past result
If she knew the millrace, she would have warned us last night.: she still does not know; the warning is past
If we were not on nights, we would have seen the tram.: present state blocking a past event

Mix the two halves when the times really are different. Do not mix them at random.

How Unreal Tenses Work

One idea: move one step back from the time you mean, then put would in the outcome.

Past Simple Means Unreal Now

After if, wish, if only, I'd rather, and as if, a past simple does not narrate yesterday. It pictures a present or future that is not the case. The negative of the form is the truth: If I knew means I do not know. Time expressions like now, today, and tomorrow can sit in the same sentence without contradiction.

If I knew the millrace now, I would not take the barge out.

knew plus now: the past form is a mood marker

Past simple after if = not true now.

Past Perfect Means Unreal Then

A past perfect after the same words pictures a past that did not happen. If I had known means I did not know. The result then takes would have plus a past participle. This is the grammar of regret, relief, and blame about a closed event.

If I had known the millrace, I would not have taken the barge out.

had known: I did not know at the time

Past perfect after if = not true then.

Would Marks the Imagined Result

The if-clause does not take would in standard English (*If I would know is wrong). Would, could, or might belongs in the result. Could and might add ability or possibility on top of the hypothesis. Would have is the past of that result, not a future in the past.

If the winch jammed, we could use the spare. If the winch had jammed, we could have used the spare.

could for present ability in a hypothesis; could have for a missed past ability

Would in the result, not in the if-clause.

Were Is the Written Form of Unreal Be

The subjunctive were appears with every subject in unreal present clauses: If I were, If she were, If it were. Speech often uses was after I and he/she/it. After wish, If I were you is a fixed piece of advice language. If I was you is widely heard and still marked as informal.

If it were quieter, I would sleep. I wish I were on the jetty.

were with it and I in unreal present

If I were, If it were, in writing.

Common Mistakes with Unreal Tenses

Incorrect: If I would know the millrace, I would wait.

Correct: If I knew the millrace, I would wait.

The if-clause takes a past simple for an unreal present, not would. Would belongs in the result clause only.

Incorrect: If I would have known, I would have waited.

Correct: If I had known, I would have waited.

The unreal past if-clause takes the past perfect, not would have. If I would have is common in some spoken varieties and is still treated as an error in standard written English.

Incorrect: I wish I will live in the lock cottage.

Correct: I wish I lived in the lock cottage.

Wish about a present state takes a past simple. Will after wish is not the grammar of a counterfactual. For a possible future, use hope: I hope I will live there.

Incorrect: It's time we leave the quarry.

Correct: It's time we left the quarry.

It's time plus a finite clause needs the unreal past simple. The infinitive It's time to leave is the way to avoid the past form.

Unreal Forms with Take

The verb take in an imagined present (would take) and an imagined past (would have taken). The if-clause is shown in the notes; the table is the result clause, which is what conjugates.

Imagined present: would + bare verb

Affirmative would take, negative would not take, question Would I take. Could and might follow the same three shapes.

Pronoun	Affirmative	Negative	Question
I	would take	would not take	Would I take?
you	would take	would not take	Would you take?
he / she / it	would take	would not take	Would she take?
we	would take	would not take	Would we take?
they	would take	would not take	Would they take?

Contractions: I'd take, she wouldn't take. Pair with If I had a lift, If she knew the millrace. The if-clause itself uses the past simple, not would.

Imagined past: would have + past participle

The participle of take is taken. Could have and might have use the same pattern.

Pronoun	Affirmative	Negative	Question
I	would have taken	would not have taken	Would I have taken?
you	would have taken	would not have taken	Would you have taken?
he / she / it	would have taken	would not have taken	Would he have taken?
we	would have taken	would not have taken	Would we have taken?
they	would have taken	would not have taken	Would they have taken?

Contractions: I'd have taken, she wouldn't have taken, I'd've taken in fast speech. Pair with If I had had a lift, If she had known the millrace.

It's Time, Would Rather, and As If

Three constructions that borrow the same unreal past without using if.

It's time

It's time plus a past simple means the action should happen now, and is slightly late.

It's time we left the quarry.: we should leave now
It's time you checked the cistern.: you are late checking it
It's time to leave the quarry.: infinitive variant, less personal

It's time we leave is a common error. The past form is required in the finite clause.

Would rather

I'd rather plus a bare verb is about the speaker's own action. I'd rather plus a past simple is about someone else's action.

I'd rather wait on the jetty.: my own action, bare verb
I'd rather you waited on the jetty.: your action, past simple
I'd rather we hadn't taken the barge.: past perfect for a past preference

I'd rather you wait is the same error as it's time we leave.

As if and as though

A past form after as if marks that the comparison is untrue or doubtful. A present form treats it as possible.

He talks as if he owned the marina.: he does not; unreal past
He looks as if he is the lock-keeper.: maybe he is; real present
She walked as though the harbour wall were ice.: were for an untrue comparison

As if he owns can be a real present. As if he owned is a comment, often critical.

Quick Check: Unreal Tenses

Put the verb in the unreal form that matches the time.

1. If the lighthouse ___ (have) a lift, we would take the crates up in one trip.

Answer: had

unreal present: past simple

2. If she ___ (radio) us, the barge would have waited.

Answer: had radioed

unreal past: past perfect

3. I wish the orchard ___ (have) a well.

Answer: had

present wish: past simple

4. It's time you ___ (check) the cistern.

Answer: checked

it's time plus past simple

5. If I had packed the visor, I ___ (be) dry now.

Answer: would be

mixed: past condition, present result

Unreal Tenses FAQs

What are unreal tenses in English?: They are past forms used to talk about situations that are not true. A past simple after if or wish pictures an imagined present: If the lighthouse had a lift (it does not). A past perfect pictures an imagined past: If the lighthouse had had a lift (it did not). The result takes would, could, or might, with or without have.
Why does English use a past tense to talk about now?: Because the past form is being used as a mood marker, not as a time marker. Moving one step back from the time you mean is how English signals that the situation is hypothetical. Many European languages use a subjunctive instead; English mostly borrows past morphology for the same job.
What is the difference between If I knew and If I had known?: If I knew is about now: I do not know. If I had known is about then: I did not know. Match the result to the same time: I would wait versus I would have waited. Mixing them is only right when the times really differ: If I had packed the visor, I would be dry now.
Should I write If I was or If I were?: Were is the traditional written form with every subject in unreal present clauses: If I were you, If it were quieter. Was is common after I and he/she/it in speech. After wish, were is still the safer choice in writing: I wish I were on the jetty.
Can I use would in the if-clause?: Not in the standard pattern for unreal present or past. If I would know and If I would have known are the usual learner errors. The exception is polite willingness: If you would wait on the jetty, I'll fetch the visor, where would means be willing to, not a hypothesis.