In a Type 2 conditional sentence, the tense in the 'if' clause is the simple past, and the tense in the main clause is the present conditional:
IF' CLAUSE | MAIN CLAUSE |
If + simple pastIf it rained |
In 'zero' conditional sentences, the tense in both parts of the sentence is the simple present:
IF' CLAUSE (CONDITION) | MAIN CLAUSE (RESULT) |
If + simple presentIf you heat ice | simple presentit melts. |
NOTE: The order of the clauses is not fixed - the 'if' clause can be first or second:
In these sentences, the time is now or always and the situation is real and possible. They are used to make statements about the real world, and often refer to general truths, such as scientific facts.
This structure is often used to give instructions, using the imperative in the main clause:
In this section you will find information on sentences containing the word 'if', the use of conditional tenses, and the 'unreal past', that is, when we use a past tense but we are not actually referring to past time.
There are four main types of 'if' sentences in English:
1. The 'zero' conditional, where the tense in both parts of the sentence is the simple present:
IF' CLAUSE | MAIN CLAUSE |
If + simple presentIf you heat ice | simple presentit melts. |
In these sentences, the time is now or always and the situation is real and possible. They are often used to refer to general truths.
2. The Type 1 conditional, where the tense in the 'if clause is the simple present, and the tense in the main clause is the simple future
IF' CLAUSE | MAIN CLAUSE |
If + simple presentIf it rains | Simple futureyou will get wet |
In these sentences, the time is the present or future and the situation is real. They refer to apossible condition and its probable result.
3. The Type 2 conditional, where the tense in the 'if' clause is the simple past, and the tense in the main clause is the present conditional:
IF' CLAUSE | MAIN CLAUSE |
If + simple pastIf it rained | Present conditionalyou would get wet |
In these sentences, the time is now or any time, and the situation is unreal. They are notbased on fact, and they refer to an unlikely or hypothetical condition and its probable result.
4. The Type 3 conditional, where the tense in the 'if' clause is the past perfect, and the tense in the main clause is the perfect conditional:
IF' CLAUSE | MAIN CLAUSE |
If + past perfectIf it had rained | Perfect conditionalyou would have got wet |
In these sentences, the time is past, and the situation is contrary to reality. The facts they are based on are the opposite of what is expressed, and they refer to an unreal past condition and its probable past result.
A further type of 'if' sentence exists, where Type 2 and Type 3 are mixed. The tense in the 'if'clause is the past perfect, and the tense in the main clause is the present conditional:
IF' CLAUSE | MAIN CLAUSE |
If + past perfectIf I had worked harder at school | Present conditionalI would have a better job now. |
In these sentences, the time is past in the 'if' clause, and present in the main clause. They refer to an unreal past condition and its probable result in the present.
This form is composed of two elements: the appropriate form of the verb to be + to (am to, are to, is to), and the infinitive of the main verb without 'to'..
Subject | to be to | infinitive without to |
We | are to | leave |
Affirmative | ||
She | is to | travel |
Negative | ||
You | are not (aren't) to | travel |
Interrogative | ||
Am | I to | travel? |
Interrogative negative | ||
Aren't | they to | travel? |
This form refers to an obligation to do something at a time later than now. It is similar to'must', but there is a suggestion that something has been arranged or organised for us. It is not normally used in spoken English, but might be found in spy stories, e.g.
This form is composed of three elements : the appropriate form of the verb to be, present tense, + 'about to' + the infinitive of the main verb without 'to':
Subject | be | about to | infinitive without to |
I | am | about to | leave |
She | is | about to | arrive |
This form refers to a time immediately after the moment of speaking, and emphasises that the event or action will happen very soon:
It is often used with the word 'just', which emphasises the immediacy of the action:
This form can also be used in the simple past tense to refer to an action that was imminent, but was interrupted. In such cases it is often followed by a 'when - clause':
This form is composed of two elements: the future perfect of the verb to be (will have been) + the present participle of the main verb (base+ing):
Subject | will have been | base+ing |
We | will have been | living |
Affirmative | ||
I | will have been | working |
Negative | ||
I | won't have been | working |
Interrogative | ||
Will | I have been | working? |
Interrogative negative | ||
Won't | I have been | working? |
Affirmative | Negative | Interrogative |
I'll have been living | I won't have been living | Will I have been living? |
You'll have been living | You won't have been living | Will you have been living? |
He'll have been living | He won't have been living | Will she have been living? |
We'll have been living | We won't have been living | Will we have been living? |
You'll have been living | You won't have been living | Will you have been living? |
They'll have been living | They won't have been living | Will they have been living? |
Like the future perfect simple, this form is used to project ourselves forward in time and to look back. It refers to events or actions in a time between now and some future time, that may be unfinished.