One difference from English grammar is that in temporal clauses referring to the future (e.g. "when you receive this, write back"), the future or future perfect tense is usually used in Latin where English uses the present. Thus the Latin equivalent is "when you will have received this, write back". In such sentences, if the main verb is an imperative, the future imperative (e.g. "write (at that time)") is used. The same tenses are used with conditional sentences starting with "if":
