The progressive verb form will always be used with a to be verb.

• I am talking to you.

• She is playing tennis.

• What are you doing?

• She isn't having a dinner party?

Progressive verb forms can be confused with gerunds.  Gerunds are verbs functioning as a noun.  

• • She is enjoying having her dinner party.

During conversation, you have to always keep your grammar monitor on to determine if -ings words are functioning as gerunds or progressive verbs.

When it comes to verbs functioning as noun in a sentence, it will be in one of three forms - the gerund (verb + ing), the infinitive with to or the infinitive without to.  The form used is a function of currently accepted grammar conventions and time period you want to capture.  This can be really tricky.  For some verbs like, hear, see, notice, recommend and watch, the -ing form or the infinitive without to can be used after the object.   

For example:

The verb “like” can be followed by:

• “I like listening to music”

• “I like to listen to music"

But not the third (“I like listen to music” is incorrect).

The verb “hear” can be followed by:

• I hear singing in the hall

But not (I hear sing in the hall / I hear to sing in the hall

Grammar in this area is very convoluted, so study and lots of practice (internalization) must be used to gain mastery -- practice makes perfect!