The document discusses different types of conditional sentences in English. It explains zero conditional uses present tense in both clauses to talk about universal truths. First conditional uses present tense in the if-clause and future tense in the main clause to talk about possible future events or make promises/warnings. Unless is used in negative conditional sentences. An example is provided for each type.

2. Conditional Sentences Structure : A conditional sentence is composed of 2 parts : If-clause + Main Clause Example : If it rains tomorrow, we will not come. If-clause Main Clause