6-18. Главная часть условного предложения

 
Теперь посмотрим, что может быть в главном клозе такого предложения.

1. imperative will be -ing, will have -en, will have been –ing

В главной части могут употребляться другие будущие грамматические времена:

If he gets the job he'll be going abroad.
If I don't run the train will have left.
If you don't hurry and get there before five o'clock, he will have left the office and gone home.
If I stay till May, I'll have been working here for 20 years.

2. imperative be going to

If we have fine weather tomorrow, I'm going to paint the windows.
What are you going to do if it rains?

3. imperative imperative

Cancel the match if it rains.
If it rains, cancel the match.
Take another sandwich if you're hungry.
If you have a mobile phone, check that it is turned off.
Come indoors at once if it rains.
Don't come unless I tell you to come.

4. imperative be + to-infinitive

What are we to do if it rains?
If he comes, what are we to do?

5. imperative modals

Если для выражения следствия из условия, выраженного в if-части предложения, глагол кажется слишком «уверенным», то можно употребить модальные с разными оттенками уверенности:

If it's fine tomorrow, we can (= we are free to) go out.
If it's fine tomorrow, we could (= we would be able to) go out.
If it's fine tomorrow, we may (= it's possible) go out.
If it's fine tomorrow, we might (= it's possible) go out.
If it's fine tomorrow, we should (= it's advisable) go out.
If it's fine tomorrow, we ought to (= it's advisable) go out.
If it's fine tomorrow, we must (= it's necessary) go out.

■ В этом случае в if-части предложения также возможны разные варианты:

If she finishes early, she can/could phone me.
If she is arriving today, she may/might phone me.
If she has arrived, she should/ought to phone me.
If she has been waiting, she phone me.
If she can't understand it, she must phone me.

И с модальными глаголами можно употреблять инфинитив в продолженной и совершенной формах:

If I hear from Tim, I may be leaving tonight
If he is in New York he may not have got my letter yet

■Чтобы подчеркнуть зависимость одного события от другого, в главном предложении можно употреблять союз then:

If she can't come to us, then we'll have to go and see her.