This document discusses conditionals in English grammar. It explains the first, second, and third conditional forms using examples. The first conditional uses "if + present" and "will + infinitive" to talk about possible future situations. The second conditional uses "if + past" and "would + infinitive" to discuss imaginary or unlikely present/future situations. The third conditional uses "if + past perfect" and "would + present perfect" to refer to imaginary past situations. It also provides alternatives to "if" such as "unless," "provided," "as long as," and "even if."