CONDITIONAL SENTENCES

In English conditional sentences, the condition clause (protasis) is most commonly introduced by the conjunction if, or sometimes other conjunctions or expressions such as unless, provided (that), providing (that) and as long as. Certain condition clauses can also be formulated using inversion without any conjunction (should you fail...; were he to die...; had they helped us...).

In English language teaching, conditional sentences are often classified under the headings zero conditional, first conditional (or conditional I), second conditional (or conditional II), third conditional (or conditional III) and mixed conditional, according to the grammatical pattern followed.[3]

"Zero conditional" refers to conditional sentences that express a simple implication (see above section), particularly when both clauses are in the present tense: "If you don't eat for a long time, you become hungry." This form of the conditional expresses the idea that a universally known fact is being described: "If you touch a flame, you burn yourself." The act of burning oneself only happens on the condition of the first clause being completed. However such sentences can be formulated with a variety of tenses (and moods), as appropriate to the situation.

More examples of the zero conditional

If you exercise a lot, you get fit

If you don't eat or drink, you die

If you eat lots of junk food, you will get fat

"First conditional" refers to predictive conditional sentences (see above section); here, normally, the condition is expressed using the present tense and the consequence using the future: "If you make a mistake, someone will let you know."

"Second conditional" refers to the pattern where the condition clause is in the past tense, and the consequence in conditional mood (using would or, in the first person and rarely, should). This is used for hypothetical, counterfactual situations in a present or future time frame (where the condition expressed is known to be false or is presented as unlikely).

If I liked parties, I would attend more of them.

If it rained tomorrow, I would dance in the street.

The past tense used in the condition clause is historically the past subjunctive; however in modern English this is identical to the past indicative except in the case of the verb be (first and third person singular), where the indicative is was and the subjunctive were. In this case either form may be used (was is more colloquial, and were more formal, although the phrase if I were you is common in colloquial language too):

If I (he, she, it) was/were rich, there would be plenty of money available for this project.

"Third conditional" is the pattern where the condition clause is in the past perfect, and the consequence is expressed using the conditional perfect. This is used to refer to hypothetical, counterfactual (or believed likely to be counterfactual) situations in the past

If you had called me, I would have come.

"Mixed conditional" usually refers to a mixture of the second and third conditionals (the counterfactual patterns). Here either the condition or the consequence, but not both, has a past time reference:

If you had done your job properly, we wouldn't be in this mess now.

If we were soldiers, we wouldn't have done it like that.

A range of variations on the above structures are possible. For details, see the article on English conditional sentences.

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A conditional sentence consists of two clauses; the if-clause, and the main clause. The if-clause can come first or second. When it comes first, we usually put a comma between the two clauses. There are 4 (four) types of conditional sentences, including mixed conditional.

1.    Conditional Sentence Type 1

→ It is possible and also very likely that the condition will be fulfilled.

Form: if + Simple Present, will-Future

Example: If I find her address, I’ll send her an invitation.

The if-clause is in the present tense, the main clause uses will and the infinitive, or simple present.

TYPE	IF CLAUSE	MAIN CLAUSE	MEANING
Type 1	Simple present If you work hard,	Simple present you succeed. Simple future you will succeed.	True in the present or possible in future It’s possible to happen in the future

When do we use conditional sentence type 1?

1. We use conditional sentence type 1 to talk about possible situations in the present or future.
• If you leave earlier, you will not be late.
• If you open the windows, the room will get some fresh air.
2. We often use conditional type 1 to talk about facts or processes:
• If you heat water to 100 degrees, it will boil.
• If we stare into the sun, we will hurt our eyes.

Note:

Other modal verbs can also be used in place of will and would.

• If it rains like this all day, the river might flood. (might = will possibly)
• If it rains like this all day, the river could flood. (could = will be able to)

2.    Conditional Sentence Type 2

→ It is possible but very unlikely, that the condition will be fulfilled.

Form: if + Simple Past, Conditional I (= would + Infinitive)

Example: If I found her address, I would send her an invitation.

The if-clause is in the simple past or the past continuous tense, the main clause uses would and the infinitive, or would be and the present participle (Verb-ing).

TYPE	IF CLAUSE	MAIN CLAUSE	MEANING
Type 2	Simple past If you worked hard, Past continuous If it were not raining now,	would + simple form you would succeed. would be + present participle I would be going out for a walk.	Untrue in the present Fact: You don’t work hard, so you don’t succeed Fact:It’s raining now, so I’m not going out for a walk.

When do we use conditional sentence type 2?

Conditional sentence type 2 is used to talk about actions or situations that are not taking place in the present or future, but we can imagine the probable result.

• If we didn’t live in a big city, we would not have to breathe polluted air everyday. (In truth, we live in a big city)
• If he were here, I would tell him about my plan.
  (In fact, he isn’t here)

Note:

• ‘Were’ is used for both singular and plural subjects.
• The use of type 2 conditional in “If I were you, I would ………” is a common form of advice.

3.    Conditional Sentence Type 3

→ It is impossible that the condition will be fulfilled because it refers to the past.

Form: if + Past Perfect, Conditional II (= would + have + Past Participle)

Example: If I had found her address, I would have sent her an invitation.

The if-clause is in the past perfect or the past perfect continuous tense, the main clause uses would have and past participle (Verb 3), or would have been and present participle (Verb-ing).

TYPE	IF CLAUSE	MAIN CLAUSE	MEANING
Type 3	Past perfect If you had worked hard, Past perfect continuous If it had not been raining yesterday afternoon,	would have + past participle you would have succeeded. would have been + present participle I would have been going out for a walk.	Untrue in the past Fact: You didn’t work hard, so you didn’t succeed. Fact: It was raining yesterday afternoon. I was not going out for a walk.

When do we use conditional sentence type 3?

Conditional sentence type 3 is used to talk about actions or situations that did not take or were not taking place in the past, but we can imagine the probable result.

• If you had come to the party last night, you would have met my cousin. (In truth, you didn’t come to the party last night)
• If he had not been late this morning, his teacher would not have punished him. (In truth, he was late)

4.    Mixed Conditional Sentence

Mixed conditional sentence is a combination of conditional sentence type 2 and conditional sentence type 3.

TYPE	IF CLAUSE	MAIN CLAUSE	MEANING
Mixed Type	Simple past If I were a bird, Past perfect If you had worked hard,	would have + past participle I would have flown to your place last night. would + simple form you would succeed.	Untrue in the present or future. Fact: I am not a bird, so I didn’t fly to your place. Untrue in the past. Fact: You didn’t work hard. Now, you don’t succeed.

When do we use mixed conditional sentence?

Mixed conditional sentence is used to talk about actions or situations that did not take or were not taking place in the past, but we can imagine the probable result in the present, or actions or situations that do not take place in the present, but we can imagine the probable result in the past.

• If you lived near the factory, you would have heard the sound of the explosion. (In truth, you don’t live near the factory. Therefore, you didn't hear the sound of the explosion.)
• If he had not been late this morning, he would be permitted to join the test. (In truth, he was late. Therefore, he is not permitted to join the test.)

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