On the other hand, Functional Grammar, developed by Simon Dik in the 1970s, is a functional approach to grammar that emphasizes the communicative function of language. This theory proposes that language is a tool for communication, and therefore, grammar should be analyzed in terms of its communicative functions. Functional Grammar seeks to explain the structure of sentences by analyzing the communicative functions of the different parts of the sentence, such as the subject, object, and verb. The goal of this approach is to explain how people use language to communicate with one another in different social contexts.

Tense refers to a location in time, aspect refers to the "fabric of time", that is single block of time, a continuous flow of time or a repetitive occurance. There are three ways to express aspect in English, namely: simple, progressive and perfect.

Aspects Aspect indicates how an action, state or an event is related to the flow of time. By looking at the aspect of a verb, we can decide whether the action is completed or ongoing. There are four aspects in English grammar They are simple, progressive, perfect and perfect progressive.

Tense and Aspect can be defined as grammatical categories that are closely related.  Therefore, the main difference between tense and aspect is that tense indicates the location of an action in time whereas aspect indicates how that particular action is to be viewed with time.

TG is a formal linguistic framework developed by Noam Chomsky in the 1950s and 1960s, which posits that there is an innate "universal grammar" that underlies all human languages. According to TG, the structure of a sentence can be described in terms of a set of underlying "deep structures" that are transformed into surface structures through a series of rules. These rules are called "transformations," and they account for the syntactic and semantic differences between sentences with similar structures.

On the other hand, FG is a functional linguistic framework that focuses on the communicative function of language. FG emphasizes the idea that language is a tool for communication, and that the structure of a sentence reflects its communicative purpose. FG analyzes language in terms of functional categories such as subject, object, and verb, and how they are used to convey meaning. It also examines the way in which language reflects social and cultural contexts and how language use varies depending on the situation.

In summary, while TG is concerned with the formal rules that generate sentences and their underlying structures, FG is concerned with the functional aspects of language use and how language is used to achieve communicative goals.

Transformational grammar contains terms like “underlying structure,” “surface structure,” and “deep structure.” Look at these two sentences:

Transformational grammar would identify the underlying structure of those sentences. They’re both united by Billy and the act of eating the apple. Their relative simplicity might lead transformational grammar to point out their surface suture. A deep structure might look like this:

As the name “deep structure” suggests, the above set of sentences takes us a little deeper into the world of Billy and why he might have consumed the apple.

As for systemic functional grammar, you could claim that SFG focuses less on individual sentences and more on the structure of language as a whole. It appears to see language as a big but limited structure. The structure provides people with many words or options. From those words or options, people craft sentences to express themselves. SFG is more focused on why people select the combination of words that they do and less focused on how those combinations of words (i.e., sentences) relate to one another.

Following this understanding, we can see that there are two tenses in English, the ‘present’ and ‘past’ tense; these are the only verbs forms that do not require an auxiliary. We add further meaning and viewpoints to these basic forms through the use of aspect. Aspect allows the speaker to interpret the events being described and express how they view them.