Every language is unique in its structure and consists of highly specific constructions. Therefore what may appear to be clear-cut and familiar linguistic categories in one language need not be present in another. In fact, no grammatical category can be said to be absolutely universal. That is why we should always refrain from imposing on an unfamiliar language the categorical distinctions that we know from other languages because there might simply not be such a notion.

A language may not have a category of tense. Instead, temporal adverbials or other categories that imply time location are used. Let's look at this phenomenon using the example of the Burmese language. Burmese doesn't have explicit grammaticalised tense. It relies on an interaction of mood markers and time adverbials. There are "real" and "unreal" situations.

Tenseless languages 

A 'real' situation is likely to have happened either in the past or right now. A 'hypothetical' situation is likely not to have taken place as of yet, and is therefore strongly associated with future time reference. Now it is clear that languages don't necessarily have to grammaticalised time location.

Interrelations of tense and aspect 

In practice it happens quite often that several categories are not easily separated. Moreover, tense and aspect can be combined into one form, like in French language. There are two distinct past tenses, both of which are distinguished by their inherent aspectual features: