Notes on the form of Type 1 conditionals

1 The most commonly used form is: 'if + simple present + "IP future If it rains, we'll stay at home However, in Type 1 conditionals, all present tenses can be used after if, not just the simple present (see 14.4 above).

2 In Type 1, if is followed by present tenses, and oply exceptionally by shall or will [> 11.63, 14.24.2]. If can also be followed by should [> 14.8] and by other modals like can (ability), must and needn't.

3 Other future tenses [> 9.40-43] can be used in the main clause: If he gets the job he'll be going abroad If I don't run the train will have left If I stay till May, I'll have been working here for 20 years

4 Fixed phrases like if necessary, if possible, if so, are really abbreviated //-clauses. In formal English (commonly in AmE) the full form is// + be (i.e. the subjunctive [> 11.75.1n.2]): if it be necessary, etc. Note other phrases with be: if need be be that as it may, etc: Inflation may be rising If (this be) so, prices will go up We often use should before be in such cases, especially when we wish to suggest that the situation referred to is improbable: Sterling may fall If this should be so, interest rates will rise

Type 1 conditionals

When we use Type 1 conditionals

We use Type 1 conditionals to describe what will or won't happen if we think a future event is probable:

Condition to be satisfied likely outcome

If the weather clears, we'll go for a walk

If the weather doesn't clear, we won't go for a walk

The condition to be satisfied is real: the weather may really clear up, and if it does, it will have a real effect. That is why such statements are often called 'open' or 'real' conditionals.

14.7 Type 1, Variation 1: 'If + present + modal

'if'-clause: present tenses main clause: modal [> 11.1]
condition to be satisfied likely outcome

simple present. If she finishes early, can/could

Present progressive If she is arriving today, may/might phone

Present perfect: If she has arrived she. should/ought to me

Presetent perfect progressive: If she has been waiting, must

modal must. If she can't understand it,

Will in the main clause expresses certainty or near-certainty [> 11.28]. If we do not feel 'certain' enough to use will, or if we want to express the idea of e.g. necessity, we can use another modal instead:

Condition to be satisfied likely outcome

can (we are free to)

could (we would be able to)
may (it's possible)

If it's fine tomorrow, we might (it's possible) go out

should (it's advisable) ought to (it's advisable) must (it's necessary)

Progressive and perfect combinations with modals are possible: If I hear from Tim, I may be leaving tonight If he is in New York he may not have got my letter yet

14.8 Type 1, Variation 2: 'If + should' + e.g. imperative