Aspect

the moment under consideration (present, past or future) or during a certain period of time
He was watching TV at 5 o’clock.
He was watching TV all year round.

Non-continuous aspect:
extensive
a momentary action:
She dropped the plate.
a recurrent action:
I get up at 8 o’clock.
an action or state, which lasts a long period of time:
He went to school from 1958 to 1968.
an action or state of unlimited duration:
They suffer a lot.

help of the opposition of continuous and non-continuous (common) aspect forms.

Continuous form is marked by a discontinuous morpheme be + -ing.
She was playing the piano when someone knocked.

Non-continuous form is unmarked.
She played the piano twice a day.

desk. = A young man was sitting1 at the desk. (slight stylistic difference, but no meaning change)
He brought her some flowers. != He was bringing her some flowers. (meaning change)
A young man sat2 on the bench. != A young man was sitting2 on the bench. (meaning change)

Terminative and Non-Terminative Verbs

the end, he sat there and lighted up a cigarette.

2. Adverbs and Adverbial Phrases
(that actualize the aspective meaning of double aspective verbs)