what is a tenses

·         It is a grammatical category that helps locate a situation in time. The tenses can be present, past or future.

In the English language, tenses are especially important, because they also tell us about the aspect of the main verb. Consider these two sentences:

a.    I play football (Aspect: not progressive, imperfect)

2. I have been playing football (Aspect: progressive, perfect)

Both of the sentences above are in present tense (more specifically, the first one is in Present Simple, the other — in Present Perfect Continuous). But they differ in aspect.

In other opinion Tenses is...

·         "Some grammarians define a tense as an inflection of the verb--a change of meaning you achieve by altering the form of the verb. So the past tense of win is won. In this sense, English has only two tenses, present and past. But for everyday use--especially for those who are studying foreign languages--this strict definition of tense is not very helpful. There is a broader use of the word [tense]: a form of the verb phrase which gives information about aspect and time."
(John Seely, Grammar for Teachers. Oxpecker, 2007)