This document summarizes the different types of conditionals in English: Type 0 conditionals refer to general truths and use the present tense. Type 1 conditionals refer to possible future events and use the present or future tenses. Type 2 conditionals refer to unlikely or imaginary situations and use the past tense and modal verbs. Type 3 conditionals refer to unlikely past events and use the past perfect and modal verbs. There are also mixed conditionals that refer to past events affecting the present. Other conditional expressions include unless, as long as, provided/providing, or, otherwise, and supposing.