ifclause

An if clause is a subordinate clause used to express a condition in conditional sentences in English. It usually introduces an outcome that depends on the condition stated in the main clause.

Conditional sentences pair an if clause with a main clause. The most common pattern is if + present simple, followed by the main clause in a suitable tense. Commas are often used after the introductory if clause.

Zero conditional: expresses general truths and facts. Structure: if + present simple, present simple. Example: If you heat water to 100 degrees Celsius, it boils.

First conditional: real future possibility. Structure: if + present simple, will + base verb. Example: If it rains tomorrow, we will cancel the trip.

Second conditional: hypothetical present or future. Structure: if + past simple, would + base verb. Example: If I won the lottery, I would travel the world.

Third conditional: hypothetical past. Structure: if + past perfect, would have + past participle. Example: If I had studied, I would have passed.

Mixed conditionals link a past condition to a present or future result, or vice versa. Example: If I had studied, I would be working now.

Other forms use could, might, or should in the main clause (If you heat it, you could get burned). In formal style, inversion can replace if, as in Had I known... and Were she to arrive, the meaning changes slightly but remains conditional.