Ling’s clothes are covered with paint.
She has been painting the ceiling
Has been painting is the present perfect continuous.
We are interested in the activity.
It does not matter whether something has been finished or not.
In this example, the activity (painting the ceiling) has not been finished.
The ceiling was white. Now it is red.
She has painted the ceiling.
Has painted is the present perfect simple.
Here, the important thing is that something has been finished.
Has painted is a completed action.
We are interested in the result of the activity (the painted ceiling), not the activity itself.
My hands are very dirty. I’ve been fixing the car.
Joe has been eating too much recently. He should eat less.
It’s nice to see you again. What have you been doing since the last time was saw you?
Where have you been? Have you been playing tennis?
The car is OK again now. I’ve fixed it.
Somebody has eaten all my candy. The bos is empty.
Where’s the book I gave you? What have you done with it?
Have you ever played tennis?
We use the continuous to say or ask how long (for an activity that is still happening):
How long have you been reading that book?
Lisa is still writing her reports. She’s been writing it all day.
They’ve been playing tennis since 2:00.
I’m studying Spanish, but I haven’t been studying it very long.
We use the simple to say or ask how much, how many, or how many times (for completed actions):
How much of that book have you read?
Lisa has written 10 pages today.
They’ve played tennis three times this week.
I’m studying Spanish, but I haven’t leaned very much yet.
Some verbs (for example, know / like / believe ) are not normally used in the continuous:
I’ve known about it for a long time. (not I’ve been knowing)
For a list of these verbs, see Unit 4A. But note that you can use want and mean in the present perfect continuous:
I’ve been meaning to phone Pat, but I kept forgetting.