Conditional Sentence...

Conditional sentence (If Clauses) adalah kalimat pengandaian yang digunakan untuk menyatakan sesuatu yang mungkin terjadi atau mungkin tidak terjadi seperti yang diharpkan. Terdiri dari main clause (induk kalimat) dan if clause (anak kalimat).

There are three kinds of conditional sentences. Each contains a different pair of tenses with each type certain variation are posssible.

Conditional Sentences Type 1 : Possible

1.    The verb in the if-clauses is present tense, the verb in the main clause is simple future.

If he runs he will get there in time

The cat will scratch you if you pull her tail

Note: this type of sentence implies that the action in the if-clause is quite probable. The meaning here is present or future, but the verb in the main clause is in a present, not a future tense. If+will/would is only possible with certain special meaning.

2.    Possible variations of the basic form

-  Variations of the main clause. Instead of if+present+future, we may have:

  If + present + may/might (possibility)

If the fog gets thicker the plane may/might be diverted. (perhaps the plane will be diverted)

If + present + may (permission) or can (permission or ability)

If your documents are in order you may/can leave at once (permission)

If it stops snowing we can go out (permission or ability)

If + present + must, should or any expression of command, request or advice

If you want to lose weight you must /should eat less bread

If you want to lose weight you had better eat less bread

If you want to lose weight eat less bread

If you see Tom tomorrow could you ask him to see me?

If + present + another present tense

If + two present tenses is used to express automatic or habitual result

If you heat ice it turns to water (will turn is also possible)

If there is a a shortage of any product prices of that product go up

When if is used to mean as/since, a variety of tenses can be used in the main clause

Ann hates London, if she hates it why does she live there? She ought to move out (if could replace, if she hates it there). This is not of course a true conditional clause.

-  Variations of the if –clause

  Instead of if + present tense, we can have:

  If + present continuous, to indicate a present action or a future arrangement

  If you are waiting for bus (present action) you’d better join the queue

  If you are looking for Peter (present action) you’ll find him upstairs

If you are staying another night (future arrangement) I’ll ask the manager to give you a better room

If + present perrfect

If you have finished dinner I’ll ask the waiter for the bill

If he has written the letter I’ll post it

If they haven’t seen the museum we’d better go there today

Conditional Sentences Type 2

A.    The verb in the If-clause is past tense,

If I had a map I would lend it to you (but I haven’t a map. The meaning here is present)

If someone tried to blackmail me I would tell the police (but I don’t expect that anyone will try to blackmail me the meaning here is future)

There is no difference in time between the first and second types of conditional sentence. Type 2 like type 1 refers to the present or future and the past tense in the if-clause is not a true past but a subjunctive which indicates unreality as in the first example above improbability as in the second example above.

B.     Type 2 is used:

1.      When the supposition is contrary to known facts:

If I lived near my office I’d be in the time for work (But I don’t live near my office)

If I were you I’d  plant some trees round the house (but I’m not you)

2.      When we don’t expect the action in the if-clause to take place:

If a burglar came into my room at night I’d scream (but I don’t expect a burglar to come in)

If I dyed my hair blue everyone would laughat me (but I don’t intend to dye it)

Some if-clauses can have either of the above meanings:

If he left his bicycle outside someone would steal it

C.     Possible variations of the basic form

1.      Variations of the main clause

If you tried again you would suceed (certain result)

If you tried again you might suceed (possible result)

If you knew her number I could ring her up (ability)

If he had a permit he could get a job (ability or permission)

2.      If + past tense can be followed by another past tense when we wish to express automatic or habitual reactions in the past:

If anyone interrupted him he got angry (whenever anyone interrupted him)

3.      When if is used to mean “as” or “since”, a variety of tenses is possible in the main clause. If + past tense here has a past meaning. The sentence is not a true conditional.

I knew she was short of money. If you knew she was short of money you should have lent her some. Why didn’t you lend her some?

4.      Variations of if + simple past we can have:

If + past continuous

If my car was working. I would/could drive you to the station

If + past perfect

If he had taken my advice he would be a rich man now

Conditional Sentences Type 3

A.    The verb in the if-clause is in the past perfect tense, the verb in the main clause is in the perfect conditional. The time is past and the condition cannot be fulfilled because the action in the if-clause didn’t happen.

If I had known that you were coming I would have met you at the airport (but I didn’t know, so I didn’t come)

B.     A combination of types 2 and 3 is possible:

The plane I intended to catch crashed and everyone was killed. If I had caught that plane I would be dead now or I would have been killed (type 3). If I had worked harder at school I would be sitting in a comfortable office now, I wouldn’t be sweeping the streets (but I didn’t work hard at school and now I’m sweeping the streets)

C.     Had can be placed first and the If omitted (inverted)

If you had obeyed orders this disaster would not have happened

Had you obeyed orders this disaster would not have happened

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