A conditional (= a conditional sentence) is a sentence containing a conditional clause which can be introduced by the following conjunctions:

• If
• When (in case it means the same as “if”)
• In case (formal)
• Provided (that) (formal)
• As long as
• Unless

There are a few types of conditionals: zero (real), first (real), second (unreal), third (unreal) and mixed (unreal).

ZERO CONDITIONALS

This type is used to show that one action, result etc. always follows another one. In such conditionals “when” is often used instead of “if”.

Form zero conditionals like this:

WHEN/IF + PRESENT SIMPLE*, PRESENT SIMPLE*

(the most common way)

• When (if) water freezes, it becomes ice.
• When (if) I travel by plane, I never seem to keep track of time.
• If (when) I fall ill, I never go to work – I stay at home and get treatment.

*Some other present tense (Present Continuous or Perfect) can be used depending on the situation:

• If (when) I’m driving too fast, my concentration gets worse.
• I can call you if (when) I have done my homework. 

WHEN/IF + PAST SIMPLE*, PAST SIMPLE*

(the most common way)

• If (when) I misbehaved, I didn’t get candy or pocket money. 
• My mother didn’t lose her temper if (when) I didn’t listen to her. 
• My teachers were strict with us if (when) we did something wrong.

*Past Continuous can also be used depending on the situation:

• When (if) I was driving my father’s car, I always had to be super careful.
• I was never listening if (when) someone was criticizing me. 

FIRST CONDITIONALS

This type of conditionals is used to talk about events which are possible in future.

Build first conditionals like this:

IF + PRESENT SIMPLE*, FUTURE SIMPLE

(the most common way)

• If you do it, I will never talk to you.
• If you leave me, I will be so brokenhearted.
• He will give her a hand if she asks him for help.

*Some other present tense can be used depending on the situation:

• If I have finished my essay, I will send it to you.
• I will drop in on you if I’m passing your house.
• If I’ve been doing this for such a long time, I will know it inside out. 

SECOND CONDITIONALS

We use this type of conditionals to talk about unlikely situations in the present or future.

Form them like this:

IF + PAST SIMPLE*, WOULD + V

(the most common way)

• If I were** you, I would buy this car.
• If you understood me, you would agree with me.
• If he passed the test, he would let us know.

*Past Continuous can also be used depending on the situation:

• I would be so happy if I were dancing with you right now.
• If he were standing here, I would be talking to him (“would be talking” shows the continuous nature of the action).

** “were” is used with all persons (I, you, he, she, it, we, they) in second conditional sentences. It’s possible to use “was” for “I”, “he”, “she”, “it” in colloquial English but it’s not grammatically correct.

THIRD CONDITIONALS

Third conditionals are about events or situations which didn’t happen in the past.

Form them like this:

IF + PAST PERFECT, WOULD* + HAVE + V3

(the most common way)

• If I hadn’t become a doctor, I would have become a teacher.
• If you hadn’t helped me, I would have lost my job.
• In case he hadn’t taken part in the competition, he wouldn’t have earned a medal.

* “Would” can be replaced by modal verbs such as “might” and “may” to show less certainty (in all kinds of conditionals):

• If I hadn’t become a teacher, I might have become a nurse.
• He may have started his own business if he hadn’t been discouraged (Past Perfect passive).

MIXED CONDITIONALS

Mixed conditionals are used to talk about what things would be now if something had or hadn’t happened in the past.

Build them like this:

IF + PAST PERFECT, WOULD + V

• If I hadn’t taken my chance, I wouldn’t be so happy now.
• If you had done that, I don’t know what we would do now.
• If your sister had taken that flight, she would be dead now as there was a plane crash and all the passengers died.

So, let’s sum it up:

Conditional	Pattern (most common)	Example
Zero	If + present simple, present simple	If you smoke, you might develop cancer.
First	If + present simple, future simple	If I come home earlier, I will call you.
Second	If + past simple, would + V	If you were my friend, you would know what I feel.
Third	If + past perfect, would + have + V3	If you hadn’t taken the course, you wouldn’t have met John.
Mixed	If + past perfect, would + V	If you had invited Tom to the party, he would be here now.

 

 

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