Defining Conditionals in English.
In English, conditionals are statements containing two clauses that are related to one another with an “if” statement. The first clause states the condition, and the second clause states the consequence when that condition is met. Each conditional type in English fits into specific grammatical structures, which will be explained below.
Type 0 – The Zero Conditional.
Type 0 conditionals are used to express a general truth. They use the present simple tense in both clauses and demonstrate a fact that will always remain true no matter the condition. These conditionals usually describe cause and effect relationships or scientific facts.
[If + simple present] + [Subject + simple present]
For example:
If you touch a fire, you get burned.
water boils if it reaches 100 Centigrade

Type 1 – The First Conditional.
The “first conditional” is the name given to the type of the conditional that expresses a possibility that might take place in the present or the future. A present simple and a future tense that includes a “will” clause are combined in this form of the conditional sentence (or, occasionally, “can” or shall”). When you use this phrase, you are referring to things that you believe will take place sometime in the near future.
[If/unless* + subject + simple present] + [Subject + will + Infinitive]
For example:
*Unless = If + not
- Tom: Shall we go by bus or by Taxi?
Adam: If we go by bus, it will be cheaper
For Adam it is possible that they will go by bus, that’s why he says: If we go by bus, it will be cheaper.
- Unless it rains, we’ll go for a picnic by the river tomorrow. (We’ll go for a picnic by the river tomorrow if it doesn’t rain.)
Type 2 – The Second Conditional.
Type 2 conditionals are used to describe imaginary situations in the present. These sentences normally use the past simple tense in the if clause, and would + infinitive in the other clause. The main difference between type 1 and type 2 conditionals is that type 2 expresses an unlikely or impossible situation.
[If/unless* + subject + simple past] + [Subject + would + Infinitive]
*Unless = If + not
For example:
- Tom: we are going on a trip; do you like to go with us?
Adam: I am busy; I don’t have time. If I had time, I would go with you.
This means that Adam doesn’t have time in the present.
- Unless he was very ill, he would be at work. (If he wasn’t very ill, he would be at work.)
Type 3 – The Third Conditional.
Type 3 conditionals are used to describe impossible situations in the past. This means that when speaking about the past, the result of an unreal situation can never happen. Type 3 sentences use if + past perfect and would have + past participle structure. Type 3 conditionals look back at something that didn’t happen.
[If/unless* + subject + past perfect] + [Subject + would/could…. + have+ past participle]
*Unless = If + not
For example:
- Last month, Lisa was sick. Tom didn’t know that and he didn’t visit her.
Lisa: I was sick last month.
Tom: Oh, If I had known that, I would have visited you. (Tom didnt’t know that Lisa was
sick and he didn’t visit her)
- I wouldn’t have phoned him unless you’d suggested it. (I wouldn’t have phoned him if you hadn’t suggested it.)