If Conditionals

Conditional sentences are sentences which express possibility – things that will, might, should or could happen, either factually or hypothetically.  With these sentences, one thing depends upon another and these sentences allow us to express this by structuring the clauses they contain.

  • The most common sentences contain two clauses.
  • Conditional sentences are also known as Conditional Clauses.

If Clauses

With this type of conditional sentence, one clause will start with  if, e.g If you study, you will pass your exams.

The clause without the if is the main clause of the sentence, while the iclause is called the subordinate or dependent clause.

Notice how the same meaning is formed by switching the order of each clause: You will pass your exams, if you study.

Conditional sentences can sometimes use other connectives such as unless, as long as, providing/provided and when.


Four configurations of tenses

‘Zero-type conditionals

Form and meaning

The form of the zero conditional causes no problems since the present tenses are used in both clauses.





The zero conditional is normally used to talk about facts and to express general truths.


First-type conditionals

Form and meaning

The basic form for this type of conditional sentence can be seen in the chart below. As before, the order of the clauses can be changed with no change in meaning.

This type refers to future possibilities that are certain or probable.







Second-type conditionals

Form and meaning

This type is often called the hypothetical or ‘unreal’ future conditional since it is usually used to speculate about either very unlikely future situations or present and future impossibilities.







Third-type conditionals

Form and meaning

This type refers to hypothetical situations in the past. In this case we use the Past Perfect tenses in the if clause and would + have in the main clause.



Mixed conditionals

In many cases we may want to talk about events that happened or did not happen in the past and the present results of those events. Therefore, we will often need to mix clauses from different conditional types in order to get our meaning across clearly and unambiguously. For example, we might want to say:

If I’d bought the lottery ticket, we would be millionaires now.

In this sentence I want to refer to something that I did not do in the past and the possible effect that this action might have had on the present – so I use a third-conditional if clause and a second-conditional main clause.’

(TESOL Direct)

Also See: Verbs in time clauses and if clauses