The document discusses different types of conditional sentences in English: 1) Type 1 conditionals refer to probable future events and use the present simple in the if-clause and will/won't + verb in the main clause. 2) Type 2 conditionals refer to imaginary or unlikely present/future situations and use the past simple in the if-clause and would/wouldn't + verb in the main clause. 3) Type 3 conditionals refer to imaginary past situations and use the past perfect in the if-clause and would/wouldn't + have + past participle in the main clause.

1. CONDITIONALS IF...