Aspect

An aspect is a grammatical category or form that expresses the way in which time is denoted by the verb.

Aspect - Learning to express relationship with time

Aspect is an extremely common part of grammar. You already make use of it all the time, even if you don't know it. Essentially, aspect refers to how a verb is modified in order to express its relationship with time. 

For example, saying that the verb "is modified" implies a different aspect than the statement that the verb "was being modified." People generally may not even realize there is such a thing as aspect. This is because people learn how to use aspect in a natural and spontaneous way as they learn language itself—meaning, people generally know it without knowing that they know it. 

Use aspect in a sentence

For your reference, here is an example of aspect being used correctly in a sentence.

"For the holiday season, I will drive across the country in order to meet up with various members of my family in the town where I grew up." 

This is correct usage of aspect because the verb "drive" is being modified in the right way in order to express that something will be done in the future. 

Here is an example, now, of aspect being used incorrectly in a sentence. 

"The young college woman needed some help moving her books; so, since I found her very sexually attractive, I was helping her with that tomorrow." 

Here, the verb "help" has an absurd aspect within the context of the sentence. It should really say "I will help" her. 

In case you're still a little confused about aspect, here are some rules you can follow in order to make sure you are using it correctly. 

1. Aspect is naturally used whenever you want to express a relation between action and time. You don't really think about it much; in general, aspect comes very naturally to most native speakers of a given language.
2. Sometimes, you can use strange constructions of aspect for literary purposes. For example, if you were writing a story about time travel, you could say, "I met him tomorrow." This is not grammatically incorrect, since it makes sense within the right context.  

Rooted in human experience

Grammatical aspect is clearly rooted in the nature of human experience as such—in particular, the experience of the flow of time. People perform actions, and then they reflect on the actions they performed; they also plan actions, and express (both to themselves and others) what they intend to do in the future. Aspect follows naturally from these expressive needs. It is necessary to modify actions somehow in order to show their relationship with time. Aspect fulfills this purpose.

Again, the use of aspect is usually learned in a natural, organic way. For example, you didn't really need anyone to teach you not to say that you "will drive your car yesterday". You just figured out, as a child, that this is not a properly constructed statement. In a way, aspect is just built into the very structure of language itself: anytime you use a verb, that verb automatically already has some aspect or another. The important thing is to make sure the verb matches up with time correctly within the context of the sentence it is being used. But this is usually easy enough to do.