Conditional Sentences

Do you understand what these sentences imply?
Do you know what they mean?

• "If you had left earlier, you would have caught the train." or
• "You will make yourself ill if you eat all those chocolates."

They are called conditional sentences. 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

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

Conditional Sentence Type 1
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

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).

Conditional Sentence Type 2
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

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).

Conditional Sentence Type 3
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.

Mixed Conditional Sentence
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.)

source : http://www.misterguru.web.id/2011/09/conditional-sentences-type-1-type-2.html