English has three tenses: the past, the present and the future.
The present tense refers to the moment of speaking. With most English verbs the present tense is marked by the suffix –s in the third person singular but otherwise has no marking at all.
The past tense refers to a time before the moment of speaking. With most English verbs, the past tense is marked by the suffix –ed, though a number of verbs have an irregular past tense.
The future tense correlates with time later than the time of speaking.
Each of these three main tenses has four forms: the simple, the progressive, the perfect and the perfect progressive.