Present Continuous Tense
(I am doing = S+Vto be+Ving)
** Study this example situation:
       "Ann is in her car. She is on her way to work.
        She is driving to work."
This means: she is driving now, at the time of speaking. The action is not finished.
Am / is / are-ing  is the present continuous:
** I am doing something = I'm in the middle of doing something; I've started doing it and haven't finished yet.
** Often in the action is happening at the time of speaking:
        - Please quiet. I'm working now.  (Not "I work")
        - Hello, Jane. Are you enjoying the party? (Not "do you enjoy")
        - I'm tired. I'm going to bed now. Good night!
        - Where 's Nick? He's having a bath. (Not "He has a bath.")
I                                  am            (=I'm)
He / She / It               is             (=he's)
We / You / They        are           (=we're)