Conditional Sentences Type 1, Type 2, Type 3, and Mixed Conditional

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

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

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

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

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

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

• Read more about Conditional Sentence Type 0 & 1 HERE.
• To do the exercise or test on conditional sentences, go to Grammar Test: Conditional Sentence.
• To read how conditional sentence is used as a testing point in TOEFL Test, read Tips TOEFL: Strategi Mengerjakan Test TOEFL Dengan Mengenali Testing Point.
• To learn more about conditional sentences, watch the following video:

Reference:

1. Azar B.S. Understanding and Using English Grammar (2nd Ed). NJ: Prentice-Hall. Inc, 1989.
2. Thomson-Martinet (1986). A Practical English Grammar (4th Ed). Oxford: Oxford University Press.
3. Swan, M. (1980) Practical English Usage. Oxford: Oxford University Press.
4. EverydayEnglish, Conditionals in English | Daily English Conversation, https://youtu.be/jk3SKf0mFaw