Active and passive

What are tenses actually?and what are active and passive tenses?is there any more tenses than that?

[Tdol]

Active and passive are voices. Ther's debate about how many tenses there are. some say there are only two- present and past, and that the present and past perfect are just aspects of the present and past tenses. Others regard them perfect forms and the perfect progressive forms as individual tenses. The future tense is also strongly debated - some say that we use the present and past tenses to express the future, while others say that will is the future tense.

[JJM Ballantyne]

Yes, "tense" can be a controversial subject as it applies to English. In its strictest meaning, tense requires verb inflection to indicate the past, present and future.
By this definition, English has a past tense and "components"* of a present tense. There is no future tense since the verb does not inflect to indicate it.
Of course, you need to separate the grammatical concept of tense from that of time. Obviously, even without a true future tense, English is still quite capable of expressing future time.
* By components, I mean present tense inflection in English is limited to the third person singular and the use of "am/are/is" in the progressive.

[Tdol]

I agree with you on the separation of tense and time as automatic links- that might work in many languages, but does not work throughout English tense usage and certainly not in langauges that have no tenses at all. (BTW, I'm a two-tenser so I should declare an interest here)