Sunday 29 March 2015

Conditional Sentences



Conditional Sentences
Type


If-clause
Main clause

Use

0
Zero Conditional
If + Present
Simple Present
General truths
1
Real present


If + Present

Future, Imperative, ought to, should, had better, must, may, can + BARE INFINITIVE,
*Likely to happen in the present or the future
2
Unreal present
If + Past

Would, could, should, might + BARE INFINITIVE
*The supposition is contrary to known facts
*We do not expect the action in the if-clause to take place

3
Unreal past
If + Past Perfect
Would, could, might +have + past participle
*The condition can not be fulfilled, because the action of the if-clause did not happen

Notes                                                                                                              

  • Conditional sentences have two parts: one part contains the if-clause/hypothesis and usually begins with if, and the other part, which contains the main clause, contains the result of the if-clause.

  • The if-clause either precedes or follows the main clause. When the if-clause precedes the main clause, we put a comma between the two clauses. When it follows, there is no comma.
     Ex. If I were you, I would eat less.  I would eat less if I were you.

  • In Zero Conditionals, “if” can be substituted by “when”.
     Ex. If/When water reaches 100 C, it boils.

  • In the Second Conditional, “were” is more common than “was”.

  • WE NEVER USE FUTURE IN THE IF-CLAUSE. (look at special uses below)

  • Other words that introduce if-clauses are: unless, suppose/supposing, what if, provided (that), in case, but for (+gerund/noun), otherwise, on condition that, given, even if/though, whether, otherwise, or else, as long as, since, as.
    Ex. Even though you aren’t ready, you must leave tomorrow.
    You must go in time, otherwise you won’t get the job.
         But for the car breaking down, we would have come early.
    You can use my car, provided that you drive carefully.
    Supposing he’s late, will you punish him?
    Unless I get the job, I will buy a car.(=If I don’t get the job, I won’t buy a car.)

  • Special Uses of will/would: they can be used in the if-clauses of type 1 to express: polite requests, willingness or unwillingness, obstinate insistence.
     Ex. If you would help me, I would be grateful to you.
     If she will work harder, she will obtain a better salary.
     If you will go on asking silly questions, I’ll think very poorly of you

  • Special Uses of should: It is used only in type 1 if-clauses to express an action for which there is only a slight possibility that it will happen.
    Ex. If you should see a creature from another planet, what would you do? (=Should you see a creature from another planet, what would you do?)
  • Inversion
When there is should, had, were in the if-clause, the subject and the auxiliary verb can be inverted and if should be omitted.
Ex. Had I heard the burglars, I would have called the police. (= If I had heard the burglars, I would have called the police.)

Mixed Conditionals
Conditionals can be mixed. Any tense is possible if the sense and the text permit it.

If-Clause
Result

Type 1
If you are rich,
you should have paid me by now.
Type 3
Type 2
If he didn’t study hard,
he won’t pass his exam.
Type 1
Type 2
If you were kind,
you wouldn’t have talked to me like that.
Type 3
Type 3
If I had married her,
I would be rich now.
Type 2



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