Conditional sentences

Conditions or suppositions are often expressed by conditional clauses. The following forms are used to introduce conditional clauses:

If	If it rains, we shall remain at home.
Even if	Even if you run, you won’t be in time for school.
Unless	Don’t go unless I tell you (to go)
In case	In case you go out, please bring some sweets for me.
In the event (of)	In the event (of) the conference being postponed, I’ll let you know.
Provided	We shall proceed provided the weather is fine.
On condition (that)	The Chairman will agree to talk to them on condition (that) the strike is called off at once.
As / so long as	As long as you are healthy, you can run.
Whether ...or	Whether you are rich or poor, I will always remember you.

Conditional sentences – Type 1: Probable (condition possible to fulfill)

                                      

Conditions to be fulfilled	likely outcome
Present tense (If clause)	Future tense (will or Modal + infinitive)  (Main clause)
If she finishes early, (simple present tense)	she will go home.
If he is standing in the rain, (present continuous tense)	he will catch cold.
If she has arrived at the station, (present perfect tense)	she will be here soon.
If he has been travelling all night, (present perfect continuous tense)	he will need rest.
If I can afford it, (can, must)	I will buy it.
If the weather does not clear, (negative)	we will not play.

Imaginary Conditional sentences – Type 2: imaginary situations (condition in theory possible to fulfill)

                                      

Imaginary Conditions	Speculate about imaginary consequences
Unreal Past tense (If clause)	Would + verb, should+ verb (Main clause) Could (ability) might (possibility)
If he was taller, (simple present tense)	he would become a police man.
If he was standing in the rain, (present continuous tense)	he might catch cold.
If I had wings,	I would fly.
If I was/were stronger,	I would run faster.
If I were a bird,	I would fly very high.
If I were you,	I wouldn’t buy that kind of car.
If he were here,	he could help us. (ability)
If he were here,	he might help us. (possibility)
If you were absent,	you ought to / should send in an application.

Purely Imaginary Conditional sentences – Type 3: imaginary situations (condition not possible to fulfill (too late))

Conditions cannot be fulfilled - because past perfect tense (hypothetical conditions)	Purely Imaginary Conditional
Past Perfect	would + have + past participle
If I had worked harder at school,	I would have got a better job.
If I had won the match,	I would have been happy.
If I had lived in the Stone Age,	I would have been a hunter.
If he were to hear of your success, Or Should he hear of your success,	he would be happy.
Were he to hear of your success,	he would be happy.
Had you seen her,	you could have met her.

Replacing if by unless, but for, otherwise, provided, suppose

1.     If + negative                             = unless + affirmative

2.     But for                                     = if it were not for
                                                    = if it hadn’t been for

3.     Otherwise                                = if it does not happen
                                                    = if it did not happen
                                                    = if it had not happened

4.     Provided(that)                         = if + order

5.     Suppose / supposing (that)      = what if?

If he does not hurry, he won’t catch the train.

Unless he hurries, he won’t catch the train.

If he does not apologise, we will refuse to speak to him.

Unless he apologise, we will refuse to speak to him.

If there was no rain, we would have come earlier.

But for the rain, we would have come earlier.

If it were not for his help, I would have suffered.

But for his help, I would have suffered.

If you don’t work hard, you won’t succeed.

Work hard, otherwise you won’t succeed.

If you had not worked hard, you would not have succeeded.

You had worked hard, otherwise you would not have succeeded.

If you had not worked hard, you would not have succeeded.

You had worked hard, otherwise you would not have succeeded.

If you finish your work by this evening, you can have an off tomorrow.

Provided (that) you finish your work by this evening, you can have an off tomorrow.

If we miss the train, what shall we do?

Suppose / supposing (that) we miss the train, what shall we do?

She can go for picnic.

She gets better.

If she gets better, she can only go for picnic.

Unless she gets better she cannot go for picnic.

She should get better otherwise she cannot go for picnic.

Supposing that she gets better she can go for picnic

You must apply now. If not, your application will be rejected.

If you do not apply now your application will be rejected.

Unless you apply now, your application will be rejected.

You must apply now, otherwise you application will be rejected.

Supposing that you apply now, your application will not be rejected.

You will succeed. You must work hard.

If you work hard you will succeed.

Unless you work hard you will not succeed.

You must work hard otherwise you will not succeed.

Supposing that you work hard, you will succeed.

He apologises. He will be set free.

If he apoligises he will be set free.

Unless he apoligises he will not set free.

He must apoligise otherwise he will not set free.

Supposing that he apologises he will be set free.