8.28 tenses in conditional clauses

There are special rules about which tense to use in conditional sentences.

Foreign learners are often taught that there are three kinds of conditional sentence:

* the first conditional, in which the verb in the main clause is 'will' or 'shall' and the verb in the conditional clause is in the simple present tense

* the second conditional, in which the verb in the main clause is 'would' or 'should' and the verb in the conditional clause is in the simple past tense

* the third conditional, in which the verb in the main clause is 'would have' or 'should have' and the verb in the conditional clause is in the past perfect tense.

This is largely correct, but does not fully describe the normal patterns of tense in conditional clauses which are set out in the following paragraphs.