Conditional sentences
REAL & UNREAL CONDITIONALS
Some conditional clauses beginning with if suggest that a situation is real:
If anyone calls, tell him or her I’ll be back at 11:00.
Other conditional clauses beginning with if suggest that a situation is unreal:
What would you do if you won the lottery?
Real Conditionals
Use present tenses to talk about the present or unchanging relationships, and past tenses to talk about the past:
If you leave now, you’ll be home in two hours.
If water is frozen, it expands.
If I make the wrong decision then I apologize.
However, when you talk about the future, you use the present tense, not will:
I’ll give you a lift if it rains.
Unreal Conditionals
In unreal conditionals, to talk about present or future situations, we use if plus a past tense, and would plus a bare infinitive:
If my grandmother were still alive, she would be a hundred today.
I’d offer to give you a ride if I had my car here.
When you talk about something that might have happened in the past, but didn’t, then you use if plus past perfect andwould have plus past participle:
If I had known how difficult the job was, I wouldn’t have taken it.
If she hadn’t been ill, she would have gone to the theater.
In unreal conditionals, you can also use could / might / should (have) instead of would (have):
If I lived out of town, I could take up hiking.
They might have found a better motel if they had driven a few more miles.
In some unreal conditionals we use mixed tenses:
If Mike weren’t so lazy, he would have passed the exam easily.
Conditional Sentences (2)
In unreal conditionals you use if…were + to infinitive to talk about imaginary future situations:
If the technology were to become available, we would be able to expand our business.
However, notice that you cannot use this pattern with many state verbs, including know, like, remember, understand:
If I knew they were honest, I’d gladly lend them the money. (not If I were to know…)
You sometimes use this pattern to make a suggestion sound more polite:
If you were to move over, we could all sit on the bench.
If the first verb in a conditional if-clause is should, were, or had we can leave out if and put the verb at the start of the clause. You do this particularly in formal literary English:
Should any of this cost you anything, send me the bill. (If any of this should cost…)
It would be embarrassing, were she to find out the truth. (If she were to find out…)
Had they not rushed Alan to the hospital, he would have died. (If they hadn’t rushed Alan…)
You use if it was / were not for + noun to say that one situation is dependent on another situation or on a person.
When you talk about the past:
If it hadn’t been for my grandparents, I never would have gone to college.
In formal and literary language you can also use:
Had it not been for my grandparents…
You can also use but for + noun with a similar meaning:
But for John’s help, I wouldn’t have got the job. (If it hadn’t been for John’s help…)
You don’t usually use if…will in conditional sentences. However, you can use if …will when you talk about a result of something in the main clause. Compare:
Open a window if it will help you to sleep. or … if it helps you to sleep.
(Helping you sleep is the result of opening the window.)
I will be angry if it turns out that you are wrong. (Not …if it will turn out…)
(Turning out that you are wrong is not the result of being angry.)
You can also use if …will in requests:
If you will take your seats, ladies and gentlemen, we can begin the conference.
If you want to make a request more polite, you can use if …would:
If you would take your seats, ladies and gentlemen…
In a real conditional sentence, you use if …happen to, if … should, or if … should happen to to talk about something which may be possible, but is not very likely:
If you happen to be in our neighborhood, drop in and see us.
You don’t usually use this pattern in unreal conditionals:
If the North sea froze in winter, you could walk from London to Oslo. (not If the North Sea happened to freeze / should (happen to) freeze in winter…)