We form the present continuous with am/is/are + the -ing form of the verb.
- I am writing a book.
- She is listening to the radio.
- They are doing their homework.
The short forms of am/is/are are ‘m/’s/’re.
- I**‘m writing** a book.
- She**‘s listening** to the radio.
- They**‘re doing** their homework.
The negative short forms of am not/is not/are not are ‘m not/isn’t/aren’t.
- I**‘m not writing** a book.
- She isn’t listening to the radio.
- They aren’t doing their homework.
Note that we can use short forms only in negative short answers, but not in positive short answers.
- ‘Are you writing a book?’ ‘No, I’m not/I am not.’
- ‘Are you writing a book?’ ‘Yes, I am.’ (NOT Yes, I’m.)
Actions happening now
We use the present continuous for things happening now, at the moment of speaking.
- ‘What are you doing?’ ‘I**‘m watching** TV.’
Actions happening around now
We use the present continuous for temporary things that are happening around now (=not at the moment of speaking but these days, or weeks, etc.)
- I**‘m reading** a very good book at the moment. (=I’m not reading it at the moment I’m speaking, but I’m reading it these days.)
now, these days, at the moment, etc.
We use the present continuous with time expressions that mean ‘now’ or ‘around now’: now, at the moment, at present, today, these days, this week, etc.