Is a verb tense which is used to show that an ongoing action is happening now, either at the moment of speech or now in a larger sense. The present continuous can also be used to show that an action is going to take place in the near future.
Positive Structure
Subject + am/is/are + verb-ing
Example
You are learning English now.
Negative Structure
Subject + am/is/are + not + verb-ing
Example
You are not swimming now.
Function
To express habits, general truths, repeated actions or unchanging situations, emotions, and wishes.