Cambridge Grammar of English Hardback with cd-rom a comprehensive Guide

conditional clause main clause

If it rains,

| we’re going to stay in the house.

Differences in tense and modality are important to a possible or imagined

situation. In the conditional clause, tense choices express different types of

potential event; in the main clause, modal verbs are used to indicate the

unfulfilled outcome of those events.

Examples of conditional sentences

conditional clause:

main clause:

comments

possible situation

possible outcome

If they promote her,

she

’ll get a big pay rise.

there is a possibility that the event 

(present tense)

(will/shall)

will happen

If I had the money,

I

’d go on a round-the-world cruise.

the event is unlikely and is purely 

(past tense)

(would/should)

hypothetical

If he had gone there,

he 

might have enjoyed it.

the event is impossible; it did not 

(past perfect)

(might have + -ed participle)

happen

Conditional clauses can be formed with other conjunctions than if: for example,

as long as

, unless (

Û

454–456

). For the first part of this chapter (449–453)

examples are confined to clauses with if.

Conditional clauses typically precede main clauses but may also follow them: