Knowing how to conjugate in English is a persistent difficulty for many people, not only people who are learning but also people who already speak English, mastering the different tenses in English seems to be a difficult even an impossible mission for many English speakers. Mastering all tenses in English must be seen under 2 different concepts : First there is the mastery of tenses in theoretical way, which means retaining all the structures, all the tenses, in the other hand the second concept is the mastery of tenses in practical way, it means not necessarily retaining the structures of all tenses but being able to conjugate all tenses.