Conditional

Sentences containing conditional clauses like if, unless, provided are called conditional sentences. They express four types of conditions and each type has different structures and meanings.

Types	Meanings	Structures	Examples
Zero	always real and possible	simple present, simple present	If it rains, we need an umbrella.
First	possible situations in the present or future.	simple present, will/shall/can/may+v1 simple present, imperatives	If she meets me, I will help her. If you want to achieve success, work hard.
Second	the unlikely but possible situation in the present or future	simple past, would/could/might+V1	If I were a bird, I could fly high.
Third	unreal situations in the past	past perfect, would/could/might+ have+V3	If they had invited me, I could have come.

Various Structures of Conditional sentences

Positive Conditions:

• I will do it if you help me. If you like
• If you like it, you may buy it.

Negative conditions:

• If you don't work hard, you will fail the exam.
• If you don't water flowers, they die.

Interrogative conditions:

• What happens to your laptop if you leave it in the sleeping mode for the whole day?
• What will you do if he rejects your idea?

Had+ subject+ past participle:

• Had he come in time, he would have caught the bus.
• Had I saved my money, I would have bought a dress.

Things to remember:

• Sentences containing conditional clauses like if, unless, provided are called conditional sentences.
• They express four types of conditions and each type has different structures and meanings.