CONDITIONAL SENTENCE

Conditional sentence
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For the non-custodial punishment for a crime in Canada, see conditional sentence (Canada).

In grammar, conditional sentences are sentences discussing factual implications or hypothetical situations and their consequences. Languages use a variety of conditional constructions and verb forms (such as the conditional mood) to form these kinds of sentences.

Full conditional sentences contain two clauses: the condition or protasis, and the consequence or apodosis.

If it rains [condition], (then) the picnic will be cancelled [consequence].

Syntactically, the condition is the subordinate clause, and the consequence is the main clause. However, the properties of the entire sentence are primarily determined by the properties of the protasis (condition) (its tense and degree of factualness).
Contents
[hide]

* 1 Conditional sentences in English
o 1.1 Factual/predictive conditions
o 1.2 Hypothetical (counterfactual) conditions
* 2 The semantics of conditional sentences
* 3 Conditional sentences in Latin
* 4 See also
* 5 References
* 6 External links

[edit] Conditional sentences in English

English conditional sentences can be divided into the two broad classes of factual/predictive and hypothetical (counterfactual), depending on the form of the verb in the condition (protasis). The terms "factual" and "counterfactual" broadly correspond to the linguistic modalities called realis and irrealis.

[edit] Factual/predictive conditions

In these constructions, the condition clause expresses a condition the truth of which is unverified. The verb in the condition clause is in the past tense (with a past tense interpretation) or in the present tense (with a present or future tense interpretation). The result clause can be in the past, present, or future. Generally, conditional sentences of this group are in two groups, the "zero" conditional and the potential or indicative conditional. This class includes universal statements (both clauses in the present, or both clauses in the past) and predictions.

The "zero" conditional is formed with both clauses in the present tense. This construction is similar across many languages. It is used to express a certainty, a universal statement, a law of science, etc.:

If you heat water to 100 degrees celsius, it boils.
If you don't eat for a long time, you become hungry.
If the sea is stormy, the waves are high.

It is different from true conditionals because the introductory "if" can be replaced by "when" or "whenever" (e.g., "When you heat water..."), which cannot be done for true conditionals.

The potential or indicative conditional (sometimes referred to as a "first" conditional) is used more generally to express a hypothetical condition that is potentially true, but not yet verified. The conditional clause is in the present or past tense and refers to a state or event in the past. The result can be in the past, present, or future. Some examples with the condition clause in the past tense:

If she took that flight yesterday, she arrived at 10pm.
If she took that flight yesterday, she is somewhere in town today.
If she took that flight yesterday, we'll see her tomorrow.

A condition clause (protasis) in the present tense refers to a future event, a current event which may be true or untrue, or an event which could be verified in the future. The result can be in the past, present, or future:

If it's raining here now, then it was raining on the West Coast this morning.
If it's raining now, then your laundry is getting wet.
If it's raining now, there will be mushrooms to pick next week.

If it rains this afternoon, then yesterday's weather forecast was wrong.
If it rains this afternoon, your garden party is doomed.
If it rains this afternoon, everybody will stay home.

If I become President, I'll lower taxes.

Certain modal auxiliary verbs (mainly will, may, might, and could) are not usually used in the condition clause (protasis) in English:

*If it will rain this afternoon, …
*If it may have rained yesterday, …

There are exceptions, however, in which will is used exactly as in the first example, namely when the action in the if clause takes place after that in the main clause:

(The weather forecast says it's going to rain.) Well, if it will rain, we must take umbrellas.
If aspirins will cure it, I'll [I will] take a couple tonight instead of this horrible medicine.[1]

Other situations in which will can be used in an if clause include when will is not being used as an auxiliary verb, in other words when it is being used modally to express willingness, persistence, or a wish:

If you'll [you will] just hold the door open for me a moment, I can take this table out to the kitchen.
If you will keep all the windows shut, of course you'll get headaches.
If you will excuse me, I think I will slip into something more comfortable.[2][3]

In colloquial English, the imperative is sometimes used to form a conditional sentence: e.g. "go eastwards a mile and you'll see it" means "if you go eastwards a mile, you will see it".

[edit] Hypothetical (counterfactual) conditions

In these constructions, the condition clause expresses a condition that is known to be false, or presented as unlikely. The result clause contains a conditional verb form consisting of would (or could, should, might) plus a main verb in the infinitive.

The contrary-to-fact present conditional (sometimes referred to as the "second" conditional) is used to refer to a current state or event that is known to be false or improbable. The past subjunctive (or in colloquial English, simply the past tense) must be used:

If she were [colloq. was] at work today, she would know how to deal with this client.
If I were [colloq. was] the king, I could have you thrown in the dungeon.

The same structure can be used to refer to a future state or event:

If I won the lottery, I would buy a car.
If he said that to me, I would run away.

In many cases, when referring to future events, the difference between a realis and irrealis conditional is very slight:

(realis) If you leave now, you can still catch your train.
(irrealis) If you left now, you could still catch your train.

The contrary-to-fact past conditional (sometime referred to as the "third" conditional) is used to refer to contrary-to-fact past events. The pluperfect (or past perfect) is used in the condition clause.

If you had called me, I would have come.
If you had done your job properly, we wouldn't be in this mess now.

Some varieties of English regularly use would (often shortened to (I)'d) and would have (often shortened to (I)'d have) in counterfactual condition clauses, but this is often considered non-standard: If you'd leave now, you'd be on time. / If you (would)'ve told me, we could've done something about it. Such use of would is widespread especially in spoken US English in all sectors of society, but these forms are not usually used in more formal writing. Nevertheless, some reliable sources simply label this usage as acceptable US English and no longer label it as colloquial.[4][5]

There are exceptions, however, where would is used in British English too in seemingly counterfactual conditions, but these can usually be interpreted as a modal use of would: If you would listen to me once in a while, you might learn something.[6][7] In cases in which the action in the if clause takes place after that in the main clause, use of would in counterfactual conditions is however considered standard and correct usage in even formal UK and US usage: If it would make Bill happy, I'd [I would] give him the money.[8]

Should can appear in the condition clause to refer to a future event presented as possible, but unlikely, undesirable, or otherwise "remote": If I should die before I wake, …, If you should ever find yourself in such a situation, …

[edit] The semantics of conditional sentences

The material conditional operator used in logic (i.e.p \Rightarrow q) is sometimes read aloud in the form of a conditional sentence (i.e. "if p, then q"), the intuitive interpretation of conditional statements in natural language does not always correspond to the definition of this mathematical operator. Modelling the meaning of real conditional statements requires the definition of an indicative conditional, and contrary-to-fact statements require a counterfactual conditional operator, formalized in modal logic.

[edit] Conditional sentences in Latin

Conditional sentences in Latin are traditionally classified into three categories, based on grammatical structure.

* simple conditions (factual or logical implications)
o present tense [if present indicative then indicative]
o past tense [if perfect/imperfect indicative then indicative]
* future conditions
o "future more vivid" [if future indicative then future indicative]
o "future less vivid" [if present subjunctive then present subjunctive]
* contrafactual conditions
o "present contrary-to-fact" [if imperfect subjunctive then imperfect subjunctive]
o "past contrary-to-fact" [if pluperfect subjunctive then pluperfect subjunctive]

Structure of Conditional Sentences

The structure of most conditionals is very simple. There are two basic possibilities. Of course, we add many words and can use various tenses, but the basic structure is usually like this:
IF condition result
IF y = 10 2y = 20

or like this:
result IF condition
2y = 20 IF y = 10

First Conditional: real possibility

We are talking about the future. We are thinking about a particular condition or situation in the future, and the result of this condition. There is a real possibility that this condition will happen. For example, it is morning. You are at home. You plan to play tennis this afternoon. But there are some clouds in the sky. Imagine that it rains. What will you do?
IF condition result
present simple WILL + base verb
If it rains I will stay at home.

Notice that we are thinking about a future condition. It is not raining yet. But the sky is cloudy and you think that it could rain. We use the present simple tense to talk about the possible future condition. We use WILL + base verb to talk about the possible future result. The important thing about the first conditional is that there is a real possibility that the condition will happen. Here are some more examples (do you remember the two basic structures: [IF condition result] and [result IF condition]?):
IF condition result
present simple WILL + base verb
If I see Mary I will tell her.
If Tara is free tomorrow he will invite her.
If they do not pass their exam their teacher will be sad.
If it rains tomorrow will you stay at home?
If it rains tomorrow what will you do?

result IF condition
WILL + base verb present simple
I will tell Mary if I see her.
He will invite Tara if she is free tomorrow.
Their teacher will be sad if they do not pass their exam.
Will you stay at home if it rains tomorrow?
What will you do if it rains tomorrow?

WSM Image
Sometimes, we use shall, can, or may instead of will, for example: If you are good today, you can watch TV tonight.

Second Conditional: unreal possibility or dream

The second conditional is like the first conditional. We are still thinking about the future. We are thinking about a particular condition in the future, and the result of this condition. But there is not a real possibility that this condition will happen. For example, you do not have a lottery ticket. Is it possible to win? No! No lottery ticket, no win! But maybe you will buy a lottery ticket in the future. So you can think about winning in the future, like a dream. It's not very real, but it's still possible.
IF condition result
past simple WOULD + base verb
If I won the lottery I would buy a car.

Notice that we are thinking about a future condition. We use the past simple tense to talk about the future condition. We use WOULD + base verb to talk about the future result. The important thing about the second conditional is that there is an unreal possibility that the condition will happen.

Here are some more examples:
IF condition result
past simple WOULD + base verb
If I married Mary I would be happy.
If Ram became rich she would marry him.
If it snowed next July would you be surprised?
If it snowed next July what would you do?

result IF condition
WOULD + base verb past simple
I would be happy if I married Mary.
She would marry Ram if he became rich.
Would you be surprised if it snowed next July?
What would you do if it snowed next July?

WSM Image
Sometimes, we use should, could or might instead of would, for example: If I won a million dollars, I could stop working.

Third Conditional: no possibility

The first conditional and second conditionals talk about the future. With the third conditional we talk about the past. We talk about a condition in the past that did not happen. That is why there is no possibility for this condition. The third conditional is also like a dream, but with no possibility of the dream coming true.

Last week you bought a lottery ticket. But you did not win. :-(
condition result
Past Perfect WOULD HAVE + Past Participle
If I had won the lottery I would have bought a car.

Notice that we are thinking about an impossible past condition. You did not win the lottery. So the condition was not true, and that particular condition can never be true because it is finished. We use the past perfect tense to talk about the impossible past condition. We use WOULD HAVE + past participle to talk about the impossible past result. The important thing about the third conditional is that both the condition and result are impossible now.
WSM Image
Sometimes, we use should have, could have, might have instead of would have, for example: If you had bought a lottery ticket, you might have won.

Look at some more examples in the tables below:
IF condition result
past perfect WOULD HAVE + past participle
If I had seen Mary I would have told her.
If Tara had been free yesterday I would have invited her.
If they had not passed their exam their teacher would have been sad.
If it had rained yesterday would you have stayed at home?
If it had rained yesterday what would you have done?

result IF condition
WOULD HAVE + past participle past perfect
I would have told Mary if I had seen her.
I would have invited Tara if she had been free yesterday.
Their teacher would have been sad if they had not passed their exam.
Would you have stayed at home if it had rained yesterday?
What would you have done if it had rained yesterday?

Zero Conditional: certainty

We use the so-called zero conditional when the result of the condition is always true, like a scientific fact.

Take some ice. Put it in a saucepan. Heat the saucepan. What happens? The ice melts (it becomes water). You would be surprised if it did not.
IF condition result
present simple present simple
If you heat ice it melts.

Notice that we are thinking about a result that is always true for this condition. The result of the condition is an absolute certainty. We are not thinking about the future or the past, or even the present. We are thinking about a simple fact. We use the present simple tense to talk about the condition. We also use the present simple tense to talk about the result. The important thing about the zero conditional is that the condition always has the same result.
WSM Image
We can also use when instead of if, for example: When I get up late I miss my bus.

Look at some more examples in the tables below:
IF condition result
present simple present simple
If I miss the 8 o'clock bus I am late for work.
If I am late for work my boss gets angry.
If people don't eat they get hungry.
If you heat ice does it melt?

result IF condition
present simple present simple
I am late for work if I miss the 8 o'clock bus.
My boss gets angry if I am late for work.
People get hungry if they don't eat.
Does ice melt if you heat it?

Conditionals: Summary

Here is a chart to help you to visualize the basic English conditionals. Do not take the 50% and 10% figures too literally. They are just to help you.
probability conditional example time
100%
zero conditional If you heat ice, it melts. any time
50%
first conditional If it rains, I will stay at home. future
10%
second conditional If I won the lottery, I would buy a car. future
0% third conditional If I had won the lottery, I would have bought a car. past