Conditionals connect a situation with a result. The choice depends on two things: how likely the situation is, and when it happens. Use the zero conditional for something that is always true, the first conditional for a real and possible future result, the second conditional for an unreal present or future situation, and the third conditional for an unreal past. The verb form changes with the time and the speaker’s attitude toward the result. The structure depends on the clause system explained in Clauses, and the linkers come from Conjunctions.

Choosing conditionals by likelihood and time

Example	Pattern
If water freezes, it expands.	Use the zero conditional when the situation is always true or regularly true.
If the train is late, we will take a taxi.	Use the first conditional when the situation is real and possible in the present or future.
If I had more time, I would learn piano.	Use the second conditional when the situation is unreal in the present or future.
If she had left earlier, she would have arrived on time.	Use the third conditional when you imagine an unreal past situation and its result.

The most common linker is if. It introduces the condition in all main conditional patterns. Unless means if not, so unless you hurry means if you do not hurry. In case introduces a precaution: Take an umbrella in case it rains. Provided that and as long as mean only if a condition is met. They often sound more formal or more careful than if. These words can also appear in other sentence patterns, but here they introduce the condition that controls the result.

Words that introduce conditional clauses

Usage	Explanation	Example
Basic condition	Use if to introduce the condition in a neutral and very common way.	If you need help, call me.
Negative condition	Use unless to mean if not in one condition clause.	Unless it rains, we will have a picnic.
Precaution	Use in case when you do something because a problem might happen later.	Take a charger in case your phone dies.
Requirement	Use provided that when one condition must be true before something can happen.	You can borrow my bike provided that you bring it back today.
Limit condition	Use as long as when one condition is acceptable only while it continues to be true.	You can stay here as long as you are quiet.

The zero conditional describes facts, rules, habits, and natural cause and effect. The result is not a guess. It is something that is always true or regularly true. If you heat water to 100 degrees Celsius, it boils. If people do not sleep, they feel tired. It also works for instructions and fixed routines. The speaker presents the condition and result as a general truth, not as a one-time event. For a broader view of everyday tense use, compare Present Simple.

Zero conditional for general truth and routine

Example	Pattern
If you heat ice, it melts.	Use the zero conditional for facts that are always true.
If the alarm sounds, leave the building.	Use the zero conditional for rules and instructions.
If I skip breakfast, I get hungry by midmorning.	Use the zero conditional for regular cause and effect.

The pattern is if + present simple, present simple. Both clauses use present forms because the sentence states a general fact or a regular result. If the alarm rings, the doors open. If you mix red and white, you get pink. The future can still appear with present tense in this structure when the meaning is a rule or arrangement: If the train arrives late, we start the meeting without you. The form stays in the present because the sentence describes a standing pattern, not a future plan. In regular events, this also sits close to Present Continuous and Past Simple only when you move away from general truth into a specific time.

Present forms in both clauses

Subject	Infinitive	Conjugation	Example
I	work	work	If I work late, I get tired.
you	work	work	If you work quickly, you finish early.
he	work	works	If he works from home, he saves time.
she	work	works	If she works in the garden, she feels happier.
we	work	work	If we work as a team, we solve problems faster.
they	work	work	If they work in silence, they concentrate better.

Scramble

The first conditional talks about a real situation that may happen in the present or future and a likely result. The speaker sees the condition as possible. If it rains later, we will stay inside. If you finish early, you can leave before six. This form is common for warnings, promises, plans, and predictions based on a real condition. The result is not certain, but it is expected if the condition happens.

First conditional for real future results

Example	Pattern
If the weather improves, we will go out.	Use the first conditional for a real or possible situation now or later.
If you send the file now, I will check it today.	Use the first conditional for likely results.
If you call me, I will answer right away.	Use the first conditional for promises, warnings, and plans.

The usual pattern is if + present simple, will + verb. If you call now, I will answer. The order can change. The main clause can come first: I will answer if you call now. When the if clause comes first, a comma usually separates the clauses. Other modal verbs can replace will when the result is possible or necessary, but will is the default form. The tense in the if clause stays in the present because the condition is still open.

Will clause forms in the result

Subject	Infinitive	Conjugation	Example
I	go	will go	If it stops raining, I will go for a walk.
you	go	will go	If you finish early, you will go home sooner.
he	go	will go	If he feels better, he will go to the meeting.
she	go	will go	If she has time, she will go with us.
we	go	will go	If the sun comes out, we will go to the park.
they	go	will go	If the tickets are cheap, they will go too.

Scramble

The second conditional describes an unreal present or future situation. The condition is imagined, unlikely, or impossible now. The result is also imagined. If I had more time, I would learn guitar. If she lived near the office, she would walk to work. Speakers also use it for polite hypotheticals: If you wanted, I would help you. The form creates distance from reality, so it sounds less direct than the first conditional.

Second conditional for unreal situations

Example	Pattern
If I lived near the sea, I would swim every day.	Use the second conditional for an imaginary present or future situation.
If you could help me, I would be very grateful.	Use the second conditional for polite hypotheticals.
If I were you, I would take a break.	Use the second conditional to talk about dreams, advice, and unlikely outcomes.

The pattern is if + past simple, would + verb. If I won the lottery, I would travel for a year. If he knew the answer, he would tell us. After be, English often uses were in formal or careful speech: If I were you, I would wait. Common irregular forms still follow the same pattern in the if clause: If she went, if he took, if they did, if I had. The past tense here does not describe past time. It signals an unreal present or future.

Past forms in unreal conditionals

Verb	Subject	Infinitive	Conjugation	Example
	I	be	were	If I were taller, I could reach the shelf.
	I	have	had	If I had more time, I would read longer.
	I	go	went	If I went to the concert, I would need a ticket.
	I	take	took	If I took the earlier bus, I would get there on time.
	I	do	did	If I did my homework now, I would relax later.

Scramble

The third conditional talks about an unreal past. The condition did not happen, and the result did not happen either. It is used for regrets, criticism, and imagining a different past. If I had left earlier, I would have caught the train. If they had listened, they would not have made that mistake. The speaker looks back at a finished situation and imagines another outcome. For a fuller look at past forms, compare Past Simple.

Third conditional for past regrets

Example	Pattern
If I had known, I would have come earlier.	Use the third conditional for an unreal past situation.
If you had checked the map, you would not have got lost.	Use the third conditional for regret or criticism about the past.
If she had practiced more, she would have won.	Use the third conditional to imagine a different past result.

The standard third conditional pattern is if + past perfect, would have + past participle. If we had booked earlier, we would have saved money. If she had taken the job, she would have moved to Madrid. Mixed conditionals combine different times. A past cause can lead to a present result: If I had studied medicine, I would be a doctor now. A present cause can also lead to a past result in a less common pattern: If he were more careful, he would not have broken the vase yesterday. These patterns are useful in long sentences, including reported versions and tense shifts in Tense Consistency in Conditional Sentences and Indirect and Reported Speech with Conditionals.

Past perfect and mixed results

Verb	Subject	Infinitive	Conjugation	Example
third conditional	I	go	had gone	If I had gone earlier, I would have caught the first train.
third conditional	she	study	had studied	If she had studied more, she would have passed the test.
mixed conditional	I	move	had moved	If I had moved to London, I would live closer to work now.
mixed conditional	they	save	had saved	If they had saved more money, they would feel calmer today.

Scramble