Unit 10.Present perfect continuous and simple(I have been doing and I have been done.)
Present perfect continuous:We are interested in the activity. It does not matter whether something has been finished or not.
Present perfect simple: The important thing is that something has been finished.
My hands are very dirty. I've been repairing the car. The car is OK again now. I've repaired it.
We use the continuous to ask or say how long(for an activity that is still happening):
How long have you been reading that book?
We use the simple to ask or say how much, how many or how many times(completed actions):
How many pages of that book have you read?
*There are some verbs(for example, know/like/believe)that are normally not used in the continuous.引自第31页
Unit 11 How long have you(been)...? A.Compare the present and the present perfect: *Amy...
Unit 12. When...? and How long...? For and since A.Compare When...?(+past simple) and H...