Present perfect continuous

PRESENT PERFECT CONTINUOUS

- the present perfect is used to express something that happened in the past and is still important now

• I've lost my keys. (--- I don't have the keys now)

– this is present perfect SIMPLE

– it expresses something that happened or finished

• I've painted the house. (--- the house is painted)

- present perfect CONTINUOUS expresses something that started in the past and is still going on (what is important is not the result but the activity itself)

• I have been thinking about the idea for a long time. (--- I'm still thinking about it)

COMPARE:

I have eaten 10 sandwiches.

I've been eating since I came home.

- some verbs cannot make present perfect continuous:

KNOW, WANT, BELIEVE, etc.