Conditional sentences

Q: What are the two main parts that make up every conditional sentence?

A conditional sentence consists of an if-clause (the condition) and a main clause (the result).

Q: When should you place a comma between the clauses in a conditional sentence?

Use a comma when the sentence begins with the if-clause ; do not use a comma when the if-clause is placed in the middle.

Q: What sentence pattern is used to state general truths, scientific facts, and regular habits?

Use If + Simple Present, ... Simple Present .

Q: What pattern is used to talk about realistic plans or future possibilities?

Use If + Simple Present, ... will / can / may + base verb .

Q: How do you form a conditional sentence that gives an instruction, warning, or advice?

Use If + Simple Present, ... Imperative (base verb) .

Practice

English Language · Pre-Secondary One Hong Kong Attainment Test · 3 min read · Updated: 30 Oct 2026

Welcome to the World of "If"!

Hi there! Today we are going to learn about Conditional Sentences. Don't let the name scare you—you use these sentences every single day! Whenever you say things like "If it rains, I will bring an umbrella," you are making a conditional statement.

Think of a conditional sentence like a Cause and Effect machine. There is a condition (the "if" part) and a result (what happens because of the condition). In primary school, we focus on making simple conditional statements to talk about real life, give rules, and make future plans. Let's dive in!

The Golden Rule: The Two Parts of a Sentence

Every conditional sentence has two parts (clauses):

1. The If-Clause: This tells us the condition or the "trigger."
2. The Main Clause: This tells us the result or what happens next.

Important Tip: The Comma Rule
- If the sentence starts with If, you must put a comma (,) in the middle.
Example: If it is sunny, we will go to the park.
- If if is in the middle, you do not need a comma.
Example: We will go to the park if it is sunny.

Quick Takeaway: Always check for that comma if "If" is the first word!

1. Talking About Facts, Rules, and Habits

We use conditional statements to talk about things that are always true, such as scientific facts, general truths, and school rules.

Pattern:
If + Simple Present, ... Simple Present

Examples:
- If you heat ice, it melts. (Scientific fact)
- If I am late for school, my teacher is unhappy. (Habit / regular result)

Memory Trick: Think of this as the Fact Pattern. Since facts and habits do not change, both clauses stay in the simple present tense.

2. Talking About Future Possibilities and Plans

We often use conditional statements when talking about real plans and things that are likely to happen in the future.

Pattern:
If + Simple Present, ... will / can / may + base verb

Examples:
- If it rains tomorrow, I will stay at home.
- If you study hard, you will pass the test.
- If you finish your homework early, you can play in the garden.

Common Mistake Alert!
Never put "will" inside the if-clause.
Wrong: If it will rain tomorrow, I will stay at home.
Right: If it rains tomorrow, I will stay at home.

3. Giving Instructions, Warnings, and Advice

In daily life and school regulations, we also use "if" to tell people what to do or give useful advice.

Pattern:
If + Simple Present, ... Imperative (command verb)

Examples:
- If you feel unwell, tell the teacher immediately.
- If the traffic light is red, do not cross the road.

Key Takeaway: Start the result clause directly with the base verb when giving an instruction or warning.

Common Mistakes to Avoid

1. The Double "Will": Do not use "will" in both clauses.
Wrong: If you will come, I will be happy.
Right: If you come, I will be happy.

2. The Missing Comma: Forgetting the comma when "If" comes first.
Wrong: If it rains we will stay indoors.
Right: If it rains, we will stay indoors.

3. Subject-Verb Agreement: Remember the singular verb ending (-s / -es) in the present tense.
Wrong: If Peter walk fast, he will catch the bus.
Right: If Peter walks fast, he will catch the bus.

Quick Check!

Can you complete this sentence?
"If Jenny ________ (finish) her project today, she ________ (watch) a movie tonight."
(Answer: finishes / will watch! Remember that Jenny is singular, so add -es in the if-clause.)

You've got this! Keep practicing these simple patterns and they will become second nature!

References

English Language Curriculum Guide (Primary 1–6) (CDC, 2025) — Education Bureau
Pre-Secondary One Hong Kong Attainment Test General Information — Education Bureau

Quick check

Can you answer these now?

Open each question to check the key ideas from this chapter.

What are the two main parts that make up every conditional sentence?

A conditional sentence consists of an if-clause (the condition) and a main clause (the result).

When should you place a comma between the clauses in a conditional sentence?

Use a comma when the sentence begins with the if-clause; do not use a comma when the if-clause is placed in the middle.

What sentence pattern is used to state general truths, scientific facts, and regular habits?

Use If + Simple Present, ... Simple Present.

What pattern is used to talk about realistic plans or future possibilities?

Use If + Simple Present, ... will / can / may + base verb.

How do you form a conditional sentence that gives an instruction, warning, or advice?

Use If + Simple Present, ... Imperative (base verb).

Why is the sentence 'If Peter walk fast, he will catch the bus' incorrect?

It violates subject-verb agreement in the present-tense if-clause; third-person singular subjects need an -s or -es ending (Peter walks).

Ready to test yourself?

10 practice questions on this topic, with worked solutions. Multiple choice is marked as you go. No account needed.

Practise This Topic

More English Language chapters

* The content provided by thinka is generated by AI and may not always be accurate or up-to-date. Please use it as a supplementary resource and verify with official materials.

Put These Notes into Practice

Reading the notes is a great start. Now practise with unlimited AI-generated questions and get instant feedback. 100,000+ students are already improving their grades.

Start Practising Now View Pricing

Done reading? Test yourself with AI practice questions

Practise This Topic Now