Present progressive

General principles
Near future
In negative constructions
Related topics

General principles

The present progressive is a version of the present which emphasizes the fact that an action is still unfolding (or is continuing) at the time one speaks. It is formed by using the auxilary "to be" with the present participle:

I am working.
He is eating his dinner.
The cat is meowing.

Usually, the present progressive indicates that one is "in the process of" or "in the midst of" doing something. If this is the idea one wishes to communicate, the present progressive will be preferable to the simple present. If you cannot replace the verb by a form of "to be in the process of", the present progressive should probably not be used. Indications of emotion, belief, and possession are rarely conjugated in the present progressive:

I think that is right. ["I am in the process of thinking" would be awkward.]
Cheryl owns her own house. ["Cheryl is in the process of owning" would be awkward.]

In certain situations the present progressive can indicate an action which will take place in the immediate future:

I am going to the movies this evening.
They are leaving tomorrow.

Near future

To emphasize the idea of future action while using the present tense, one may use the verb "to go"; it indicates what one is going to do. In this case the principle verb remains in the infinitive:

I know he is going to yell at me!
They are going to regret that decision.

Note: The near future can also be used in past constructions, in which case the verb "to go" is conjugated in the past progressive:

She was going to leave, but the telephone rang.