We use the present perfect continuous for an action that has just stopped. There is a connection with now :

e.g.:

1. She has been reading for two hours now.

2. Why are your clothes so dirty? What have you been doing? 

We often use the present perfect continuous with how long , for and since.

e.g.:

1. How long have you been learning English?

2. It has been raining for tow hours.

3. It has been raining since the morning.

You can use the present perfect continuous for actions repeated over a period of time:

e.g.:

Every morning they meet in the same café. They have been going there for years.