CONDITIONAL SENTENCES

Conditional sentences are sentences expressing factual implications, or hypothetical situations and their consequences. They are so called because the validity of the main clause of the sentence is conditional on the existence of certain circumstances, which may be expressed in a dependent clause or may be understood from the context.

A full conditional sentence (one which expresses the condition as well as its consequences) therefore contains two clauses: the dependent clause expressing the condition, called the protasis; and the main clause expressing the consequence, called the apodosis. An example of such a sentence (in English) is the following:

If it rains, the picnic will be cancelled.

Here the condition is expressed by the clause "If it rains", this being the protasis, while the consequence is expressed by "the picnic will be cancelled", this being the apodosis. (The protasis may either precede or follow the apodosis; it is equally possible to say "The picnic will be cancelled if it rains".)

Languages use a variety of grammatical forms and constructions in conditional sentences. The forms of verbs used in the protasis and apodosis are often subject to particular rules as regards their tense and mood. Many languages have a specialized type of verb form called the conditional mood – broadly equivalent in meaning to the English "would (do something)" – for use in some types of conditional sentence.

Conditional tenses are used to speculate about what could happen, what might have happened, and what we wish would happen. In English, most sentences using the conditional contain the word if. Many conditional forms in English are used in sentences that include verbs in one of the past tenses. This usage is referred to as "the unreal past" because we use a past tense but we are not actually referring to something that happened in the past. There are five main ways of constructing conditional sentences in English. In all cases, these sentences are made up of an if clause and a main clause. In many negative conditional sentences, there is an equivalent sentence construction using "unless" instead of "if".

THE ZERO CONDITIONAL

The zero conditional is used for when the time being referred to is now or always and the situation is real and possible. The zero conditional is often used to refer to general truths. The tense in both parts of the sentence is the simple present. In zero conditional sentences, the word "if" can usually be replaced by the word "when" without changing the meaning. 

From:

If + Simple Present, + Simple Present

Examples:

• If you run, you sweat.
• If I drink a lot of alcohol, I get a hangover.
• If it’s icy, the floor is slippery.

In all of the above examples, the second event is only true if the first event happens.

TYPE 1 CONDITIONAL

The type 1 conditional refers to a possible condition and its probable result. These sentences are based on facts, and they are used to make statements about the real world, and about particular situations. We often use such sentences to give warnings. In type 1 conditional sentences, the time is the present or future and the situation is real. These situations take place if a certain condition is met. It is possible and also very likely that the condition will be fulfilled.

Form:

If + Simple Present, + Simple Future

Examples:

• If it is sunny, I will go to the beach.
• If she does well in the competition, she will get the reward.
• If Takumi asks Hachiko to marry her, she will say “yes”.

In all of these examples, the second event is only true where the first event or condition is completed.

TYPE 2 CONDITIONAL

The type 2 conditional is used to refer to a time that is now or any time, and a situation that is unreal. These sentences are not based on fact. The type 2 conditional is used to refer to a hypothetical condition and its probable result. In type 2 conditional sentences, the if clause uses the simple past, and the main clause uses the present conditional.

Form:

if + Simple Past, + would + infinitive

Were / Was

In conditional type 2, we usually use in the if clause "were" instead of "was" even if the pronoun is I, he, she or it. "were" here is a subjunctive form.

NOTE: "was" is also a possible form.

Examples:

• If I won the lottery, I would buy a huge mansion.
• If Kurt lived in New York, she would live in Manhattan.
• If Kaneki was a vegetarian, he wouldn’t eat meat.

All of the above examples are technically possible situations (it’s possible to win the lottery, if you play) but they are all very unlikely situations. To express this, we use the second conditional tense.

TYPE 3 CONDITIONAL

The type 3 conditional is used to refer to a time that is in the past, and a situation that is contrary to reality. The facts they are based on are the opposite of what is expressed. The type 3 conditional is used to refer to an unreal past condition and its probable past result. In type 3 conditional sentences, the if clause uses the past perfect, and the main clause uses the perfect conditional.

Form:

if + Past Perfect, + would + have + Past Participle

Examples:

• If I had been born in France, I would have spoken French.
• If Helen had seen the painting first, she might have bought it.
• If Craig hadn’t been born in Oxford, he would have had a very different accent.

Using " unless"

"Unless" means the same as "if ... not", and has a negative value. It is frequently (but not only) used in conditional statements where the verb of the main clause is also  in the negative.

      You wouldn't have fallen over unless there'd been a banana skin on the ground.
-->You wouldn't have fallen over if there hadn't been a banana skin on the ground. 

Things to remember

1. The main clause can also be at the beginning of the sentence. In this case, don't use a comma.

Examples:

• "Phosphorus burns if you expose it to air."
• " I will send her an invitation if I find her address."
• " I would travel around the world if I had a million dollars."
• "He wouldn't have had that terrible accident if he had been careful."

2. Main clause and/or if clause might be negative.

Example:

• If I don’t see him this afternoon, I will phone him in the evening.
• If he had been careful, he wouldn't have had an accident.

Another Way to Explain Conditional Sentences

You have probably noticed that different teachers, textbooks, and Web sites sometimes explain the same thing in different ways. This seems to be especially true of conditional sentences. However, two different explanations can both be correct, especially if the difference is due to the fact that complicated material has been organized in different ways. This is often true of explanations of conditionals that you find in your textbooks. Here conditional sentences are divided into three types based on their meanings: real, predictive, and imaginative conditional sentences.

A. Real conditional sentences can express generalizations and inferences.

1. Generalizations include facts that are always true and never change, and they include present or past habitual activities that are or were usually true.

Examples of real conditional sentences expressing facts:

If water boils, it turns to steam.

2. Inferences are often expressed in real conditional sentences.

Real conditionals expressing inferences usually have parallel verb phrases in both clauses. However, if a modal which explicitly expresses an inference (must or should, for example) is used in the main clause, parallel verb phrases are not used.

Examples of real conditional sentences expressing inferences:

If today is Wednesday, it is George’s birthday.

B. Predictive conditional sentences can express predictions and plans.

1. Predictive conditional sentences usually contain simple present tense in the if-clause and will or be going to in the result clause. However, a weaker modal of prediction (may or should, for example) can be used in the result clause to express less certainty.

2. Examples of predictive conditional sentences:

If the exam is hard, many students are going to fail.

C. Imaginative conditional sentences are the most difficult for many learners of English because of the unusual relationship between form (the tenses used) and meaning.

In this type of conditional sentence, past tense refers to present or future time; past perfect tense refers to past time. Another problem for many learners of English is that were (not was) is used with singular subjects. Be is the only English verb with two past tense forms, but only one of them (were) is used in imaginative conditional sentences.

Imaginative conditional sentences can express hypothetical or contrary-to-fact events or states.

1. Hypothetical events or states are unlikely but possible in the present or future.

Imaginative conditional sentences expressing hypothetical events or states have a past tense verb in the if-clause and would + verb (or might or could + verb) in the result clause.

Examples of hypothetical conditional sentences (present and/or future time):

• If George had enough money, he would buy a new car.
• If I won the lottery, I would buy you a present.
• If she knew the answer, she would tell us.

(George probably does not have enough money; I probably will not win the lottery; she probably does not know the answer.)

2. Contrary-to-fact events or states are either impossible in the present time or did not happen in the past.

Imaginative conditional sentences expressing present contrary-to-fact events or states have a past verb in the if-clause and would + verb (or might or could + verb) in the result clause. Some examples:

• If I were you, I would not do that.
• If she studied for exams, she would get better grades.
• If it were raining, the streets would be wet.

(I am not you; she doesn’t study for exams; it isn’t raining.)

Imaginative conditional sentences expressing past contrary-to-fact events or states have a past perfect verb in the if-clause and would + have + verb (or might or could + have + verb) in the result clause. Some examples:

• If George had had enough money, he would have bought a new car.
• If I had won the lottery, I would have bought you a present.
• If she had known the answer, she would have told us.

(George did not have enough money; I did not win the lottery; she did not know the answer.)

Test on Conditional Sentences Type 1, 2 and 3

1. If you (go) ....out with your friends tonight, I (watch) ....the football match on TV.
2. I (earn) ....a lot of money if I (get) ....that job.
3. If she (hurry / not) ...., we (miss) ....the bus.
4. If he (try) ....harder, he (reach) ....his goals.
5. I (buy) ....these shoes if they (fit).
6. It (surprise / not) ....me if he (know / not) ....the answer.
7. If we (listen) ....to the radio, we (hear) ....the news.
8. If you (switch) ....on the lights, you (fall / not) ....over the chair.
9. She (come) ....to our party if she (be / not) .... on holiday.

scroll down for answers!

Answers!

1. If you go out with your friends tonight, I will watch the football match on TV.
2. I will earn a lot of money if I get that job.
3. If she does not hurry, we will miss the bus.
4. If he tried harder, he would reach his goals.
5. I would buy these shoes if they fitted.
6. It would not surprise me if he did not know the answer.
7. If we had listened to the radio, we would have heard the news.
8. If you had switched on the lights, you would not have fallen over the chair.
9. She would have come to our party if she had not been on holiday.

Sources and Test:

http://linguapress.com/grammar/conditionals.htm

http://istudyenglishonline.com/english-tenses/conditional/

http://www.edufind.com/english-grammar/conditional/

https://en.wikipedia.org/wiki/Conditional_sentence

https://www.ego4u.com/en/cram-up/grammar/conditional-sentences\

http://faculty.deanza.edu/flemingjohn/stories/storyReader$18

https://www.ego4u.com/en/cram-up/tests/conditional-sentences-3