Guide to English grammar

Have I/you/we/they been waiting?
Has he/she/it been waiting?

2 Use
1 We use the present perfect continuous for an action over a period of time up to now, the period leading up to the present.

I've been waiting for three years.
The government has been cutting expenditure.
How long have you been using a wheelchair?
The roof has been leaking. The carpet's wet.
The speaker looks back from the present and so uses the perfect.
NOT I wait for three years.
We often use for and since. • 227(5)
We've been living here for six months/since April.

NOTE
The action can end just before the present.

You look hot. -Yes, I've been running.

2 We can use the present perfect continuous for repeated actions up to now.

David has been writing letters to the hospital.
I've been going to evening classes in Arabic.
The speaker sees the actions as a continuing series.
Compare the present perfect for a complete series of actions.
David has written to the hospital three times now.

3 Compare the present perfect continuous and the present perfect for a single action.

Period of time Complete action

I've been washing the car. I'm rather wet. I've washed the car. It looks a lot cleaner now.

The continuous here focuses on the action going on. The present perfect focuses on the result of the action. The choice depends on how the speaker sees the action.
When we say how long, we normally use the continuous form. When we say how many, we do not use the continuous.
Tina has been writing her report since two o'clock.
She's written twelve pages.
Now look at these examples.
I've been waiting here for ages./I've waited here for ages.
We've been living here since April/We've lived here since April.
The continuous is more usual here, but there is little difference in meaning.

4 We use the present perfect (not the continuous) for a state up to the present.

She has been in a wheelchair for three years.
I