Date: 23.06.2026 Time: 9.00 am -1.00 pm

Lecturer: Dr. D.N. Aloysius

Lesson: Conditional Sentences

International Diploma in English (ICBT Campus) Anuradhapura

Learning Outcomes

By the end of this lesson, students will be able to:

·         Identify different types of conditional sentences.

·         Understand the structure and usage of Zero, First, Second, and Third Conditionals.

·         Form grammatically correct conditional sentences.

·         Use conditionals appropriately in speaking and writing.

1. Introduction to Conditional Sentences

A conditional sentence expresses a condition and its result.

A conditional sentence usually consists of two clauses:

1.     If-clause (condition)

2.     Main clause (result)

Structure

If + condition, result

or

Result + if + condition

Examples

·         If it rains, we will stay at home.

·         We will stay at home if it rains.

Note: When the if-clause comes first, use a comma (,). When it comes second, no comma is needed.

 

 

2. Zero Conditional

Usage

The Zero Conditional is used for:

·         Scientific facts

·         General truths

·         Habits and routines

·         Situations that are always true

Structure

If + Present Simple, Present Simple

Formula

If + Subject + V1, Subject + V1

Examples

·         If you heat water to 100°C, it boils.

·         If people don't eat, they get hungry.

·         If it rains, the ground becomes wet.

·         If I drink coffee at night, I cannot sleep.

More Examples

If-Clause	Main Clause
If you touch fire	it burns you
If plants do not get water	they die
If the sun sets	it becomes dark

Key Rule

Both clauses are in the Simple Present Tense.

 

 

3. First Conditional (Conditional Type 1)

Usage

The First Conditional is used for:

·         Real and possible future situations

·         Predictions

·         Warnings

·         Promises

Structure

If + Present Simple, will + Base Verb

Formula

If + Subject + V1, Subject + will + V1

Examples

·         If it rains tomorrow, we will cancel the match.

·         If you study hard, you will pass the exam.

·         If she arrives early, we will start the meeting.

·         If I see him, I will tell him the news.

Negative Form

·         If you do not hurry, you will miss the bus.

·         If she doesn't practice, she will not improve.

Question Form

·         What will you do if it rains?

·         Will you come if I invite you?

Key Rule

Do not use "will" in the if-clause.

❌ If it will rain, we will stay home.

✅ If it rains, we will stay home.

4. Second Conditional (Conditional Type 2)

Usage

The Second Conditional is used for:

·         Unreal or imaginary situations in the present

·         Hypothetical situations

·         Dreams and wishes

·         Advice

Structure

If + Past Simple, would + Base Verb

Formula

If + Subject + V2, Subject + would + V1

Examples

·         If I had a million dollars, I would buy a house.

·         If she knew the answer, she would tell us.

·         If I lived in London, I would visit museums every week.

·         If they worked harder, they would succeed.

Special Rule: "Were"

For formal English, use were for all subjects.

·         If I were rich, I would travel around the world.

·         If he were here, he would help us.

Negative Form

·         If I were not busy, I would join you.

·         If she didn't live far away, she would visit us often.

Question Form

·         What would you do if you won a lottery?

·         Where would you live if you could choose any country?

 

Key Rule

The situation is unreal or unlikely in the present.

5. Third Conditional (Conditional Type 3)

Usage

The Third Conditional is used for:

·         Unreal situations in the past

·         Regrets

·         Criticism

·         Imagining different past results

Structure

If + Past Perfect, would have + Past Participle

Formula

If + Subject + had + V3, Subject + would have + V3

Examples

·         If I had studied harder, I would have passed the exam.

·         If she had left earlier, she would have caught the train.

·         If they had listened to the teacher, they would have understood the lesson.

·         If we had known about the meeting, we would have attended it.

Negative Form

·         If he had not forgotten the key, he would have entered the house.

·         If I had not overslept, I would have arrived on time.

Question Form

·         What would you have done if you had seen the accident?

·         Would you have helped if you had been there?

 

 

 

Key Rule

The action cannot be changed because it happened in the past.

6. Summary Table

Conditional Type	Structure	Usage	Example
Zero Conditional	If + Present Simple, Present Simple	Facts and truths	If water reaches 100°C, it boils.
First Conditional	If + Present Simple, will + V1	Real future possibility	If it rains, we will stay home.
Second Conditional	If + Past Simple, would + V1	Unreal present/future	If I were rich, I would travel.
Third Conditional	If + Past Perfect, would have + V3	Unreal past	If I had studied, I would have passed.

7. Other Modal Verbs in Conditionals

Instead of will or would, other modal verbs may be used.

First Conditional

·         If you finish early, you can leave.

·         If you study well, you may pass.

Second Conditional

·         If I had more time, I could learn French.

·         If she tried harder, she might succeed.

Third Conditional

·         If he had trained more, he could have won.

·         If they had planned properly, they might have avoided the problem.

 

 

 

 

8. Common Errors

Error 1

❌ If I will see him, I will tell him.

✅ If I see him, I will tell him.

Error 2

❌ If I would be rich, I would travel.

✅ If I were rich, I would travel.

Error 3

❌ If she studied harder, she will pass.

✅ If she studies harder, she will pass. (First Conditional)

OR

✅ If she studied harder, she would pass. (Second Conditional)

Error 4

❌ If I had known, I would tell you.

✅ If I had known, I would have told you.

9. Practice Exercise

A. Complete the Sentences

1.     If you heat ice, it __________. (melt)

2.     If it rains tomorrow, we __________ at home. (stay)

3.     If I were the president, I __________ new laws. (introduce)

4.     If she had studied harder, she __________ the exam. (pass)

B. Identify the Conditional Type

1.     If I had seen you, I would have spoken to you.

2.     If people eat too much, they gain weight.

3.     If she calls me, I will help her.

4.     If I were a bird, I would fly around the world.

Pair Work

Ask and answer:

1.     What will you do if you pass your diploma?

2.     If you were the principal of ICBT Campus, what would you change?

3.     What would you have done if you had missed today's class?

4.     What happens if students do not attend lectures regularly?

Conclusion

Conditional sentences help us talk about:

·         Facts (Zero Conditional)

·         Real future possibilities (First Conditional)

·         Imaginary present or future situations (Second Conditional)

·         Unreal past situations and regrets (Third Conditional)

Mastering these four conditional structures will significantly improve accuracy and fluency in academic and professional English communication.

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