English Grammar - Conditional sentences and Its Types

CONDITIONAL SENTENCES

There are several structures in English that we call conditionals or if conditionals. The word "condition" means "situation or circumstance". Conditional sentences are statements discussing known factors or hypothetical situations and their consequences. If a particular condition is true, then a particular result happens:

Rules Of Conditional Sentences:

1. It has two parts: (a) ' if ' clause and (b) main clause
2.  1. 'If ' clause contains word 'if '.
3. The modals (will, would, can, could, may and might often appear in main clause)
4. The 'if' clause can come at the beginning or at the end.
5. When the 'if' clause comes at the beginning, it is separated from the main clause by a comma.

Types Of Conditional Sentences:
There are three basic English conditionals plus the so-called zero conditional. So, altogether there are four types of conditional sentences in English. Which are:

1. Zero Conditional Sentences:
2. First Conditional Sentences:
3. Second Conditional Sentences:
4. Third Conditional Sentences:

These types may be real conditions (possibly true) or unreal conditions (not true).

• Real conditions show something occurs in present or future. It is factual, habitual or commands.
• Unreal conditions show something occurs either in present or future time or in past time. It describes situations that are unlikely, untrue, or impossible.

Structure of Conditional Sentences
The structure of most conditionals is very simple. There are two ways to describe them.

For example:
If I see him, I will tell him.
I will tell him if I see him.
Notice the comma in the first sentence. In the second sentence we do not normally use a comma.

Rules For Conditional 

1. Zero Conditional Sentences:

• Zero conditional sentences are used to talk about general truths, scientific facts and always true.
• In zero conditional sentences, 'when' can also be used instead of ' if ' in 'if 'clause, but the meaning of the sentence will be the same.
• Both parts ('if 'clause and main clause) are in simple present tense.

If Clause,	Main Clause
If + Simple present tense,	Simple present tense
e.g. If + you heat ice,	it melts

Examples:

• If you heat the water to 100 degrees C, it boils.
• If you heat ice, it melts.
• We get tired when we don't get enough sleep.
• My boss gets angry if I am late for work.

2. First Conditional Sentences Or Type 1 Conditional Sentences (for real possibility):

1. First conditional sentences used for future.
2. It is real condition sentences.
3. It shows routine or habitual and factual situations.
4. We are talking about the future. We are thinking about a particular condition or situation in the future, and the result of this condition.
5. There is a real possibility that this condition will happen.

Future Time

If Clause,	Main Clause
If + Simple present tense,	will / can / may / must + base verb
e.g. If + it rains,	I will + stay at home

Examples:

1. If I have enough money, I will buy a new car.
   
2. If I see him, I will tell him.
   
3. If I win prize bond, I will buy a car.
4. Imagine that it rains. What will you do?
5. We will have plenty of time to finish this project if it is only ten o'clock now.
6. If I have the time, I will go.
   (Means: I will go unless I do not have time.)
7. If my headache disappear, we can play tennis.
   (Means: I will play tennis unless I have a headache.)

Habitual

If Clause,	Main Clause
If + Simple present tense,	Simple present tense
e.g. If + John has enough time,	he usually walks to school.

Examples:

1. If the doctor has morning clinic hours, he visits his patients in the hospital in the afternoon.
2. You are at home if it is morning.
3. You plan to play cricket this evening. But there are some clouds in the sky.

Commands

If Clause,	Main Clause
If + Simple present tense,	Command form
e.g. If + you hear from Sana,	please call me

Examples:

• If you go to post office, please mail this letter for me.

Second Conditional Sentences Or Type 2 Conditional Sentences:

1. Used for present or future.
2. It shows unreal situations.
3. Second conditional sentences are often used for talking about imaginary or unreal and hypothetical or impossible in the present or past.
4. The verb in the clause with 'if' is in the simple past or past continuous tense.
5. The verb in the other clause uses the modal 'would' (in negative sentences 'wouldn't' is often used). Other modals that can also be used are 'could' and 'might' and their negative forms (couldn't, might not).
6. The past form of "be" is always "were" (when 'be' verb use as main verb) in 'if' clause. It can never be "was".
   (e.g. If I were, If you were, If he were, If she were, If it were, If they we were , If they were etc.)
7. If the verb is in negative form in the 'if' clause. the sense of the sentence is positive, and if a verb is in positive form in the 'if' clause, the sense of the sentence is negative.

If Clause,	Main Clause
If + Simple past or Past continuous	would / could / might + base verb
e.g. If + they allowed,	they would + sleep the whole day.
e.g. If + he was coming,	they would + go for walk.
If +Sub + were,	modals  + base verb
e.g. If + I+ were a millionaire,	I would  + buy a yacht

Examples:

• If I had money, I would give you.
  (Means: I don't have money)
• If they drank sufficient water, they would have a healthy skin.
• If Sana was watching television, the lights would be on.
• I would go mad if I received a billion rupees.
• If I were rich, I would travel around the world.
  (Means: I am not rich, I am not going to travel around the world.)
• If I hadn't be in a hurry, I wouldn't spill the milk.
  (Means: I was in hurry, I spilled the milk.)
• If I had the time, I would go.
  (Means: I know I don't have time and therefor, I can't go.)
• If today were Saturday, we could go to the beach.
  (Means: Today is not Saturday, so we can't go to the beach.)
• If he did not speak so quickly, you could understand him.
  (Means: He speaks very quickly, so you can't understand him.)

Third Conditional Sentences Or Type 3 Conditional Sentences:

1. Not possible now
2. Used for past unreal situations.
3. The verb in "if-clause' is in past perfect tense.
4. If two actions happened at quite different times, the verb should show that difference.
5. In unreal condition sentences word 'if' is not use than sentence start with word 'had'.

If Clause,	Main Clause
If + Past perfect	would / could / might + have + verb in past participle
e.g. If + I had met John last week,	I would + have + given him a book.
had+  Verb in past participle	would / could / might + have + verb in past participle
e.g. had + we known that you were there,	we would + have + given you a book.

Examples:

• If he had talked to me, I would have listened to him.
  (but he didn't talk to me)
• If we had known that you were there, we would have written you a letter.
  (Means: We did not know that you are there, so we did not write you a letter.)
• If we hadn't lost our way, we would have arrived sooner.
  (Means: We lost our way, so we did not arrive earlier.)
• If she had seen the movie, she would have told you.
  (It shows that actions happened at different time.)

Uses of Different words in conditional sentences.

As if / As though

1. They also indicate unreal condition.
2. They use as conjunctions.
3. The verb follow should be in past or past perfect.

Main Clause	as if / as though Clause
Subject + Verb (present) +	as if / as though + subject + verb (past)

Examples:

• The old lady dresses as if it were winter even in the summer.
  (It is not winter.)
• Angelina walks as though she studied modelling.
  (She did not study modelling.)
• He acts as though as he was rich.
  (He is not rich.)

Main Clause,	If Clause
Subject + Verb (past) +	as if / as though + subject + verb (past perfect)

Examples:

• Betty talked about the contest as she had won the grand prize.
  (She did not win the grand prize.)
• He looked as though he had run ten miles.
  (He didn't run ten miles.)

Note: Conjunctions (as if / as though), if are not followed by above given tenses they have same meaning as mention in sentence.

e.g. He looks as if he finish the test. (Perhaps he has finished.)
He looked as though he was leaving. ( Perhaps he was leaving.)

Mixed Conditional Sentences

Third condition	Second condition
If  you had done what I said,	you would be rich now.

Second condition	Third condition
If I was faster,	I would have won that race.