please help i really dont know how to us these sentences so could you please help me?

Hello chhiring sherpa;

Welcome to English Forums.

The verb forms in your sentences are present perfect continuous.
Modal auxiliaries are used with all the tenses.
They add the same meaning of obligation, ability, possibility, or being less direct.

Here are the basic sentences without the auxiliaries:
I have been doing it.
You have been doing it.

Thank you so much.Actually, I know how to form a sentence but the problem is that I don't know when to use it ands what it means.
Like ,
(I could have been doing it )does it mean that I could continue it but I didn't. So can you please explain it to me briefly of all and what do the all above sentences mean ?

I really have no idea.

chhiring sherpa(I could have been doing it )does it mean that I could continue it but I didn't.

No, in this case it means "possibility" as in this conversation:

A: What were you doing on May 17, 2012 at 7:00 pm?
B: I don't remember. Let me think. I was still in school, and my baby brother was just 2 months old. So I could have been studying

chhiring sherpaA. I could have been doing it.

1. It's possible that I was doing it. (I am not sure.) (Maybe I've forgotten, and maybe I wasn't aware at the time that I was doing it.)
— Were you having breakfast at 9 a.m. last August 12?
— I often have breakfast at that time, but that was long ago. I don't know. I suppose I could have been

chhiring sherpaA.I could have been doing it B.you should have been doing itc.he would have been doing it

Just a passing comment....
This is actually a (type 3) perfect conditional continuous statement which typically is followed by an "if " clause; e.g. If John hadn't been injured in a ski accident last year, he would have been working in Shanghai right n

Thank you very much,appreciated. I have one more question.

A.you may have been playing with your friends.does this sentence mean "may be you were playing with your friends but I am not sure at the time of speaking wheather you were playing or not.

B. I could have been making you fool.does it mean it was possible to keep making you fool but the reality is that I wasn't making yo

grammarfreakThis is actually a (type 3) perfect conditional continuous statement which typically is followed by an "if " clause; e.g. If John hadn't been injured in a ski accident last year, he would have been working in Shanghai right now.

Not necessarily.

There is no condition, not even an implied one in:

I should have been looking after

chhiring sherpaA.you may have been playing with your friends.does this sentence mean "may be you were playing with your friends but I am not sure at the time of speaking whether you were playing or not.

Maybe (one word) you were playing with your friends. (You are correct in your understanding.)

chhiring sherpaB. I could have bee

One more question ,sir.I am not still clear about using would have been doing .what I have understood yet about it is that would have been doing or would have done can be used in two ways. First one is if clause like if I say if I had known that you were in hospital, I would have visited you or I would have been helping you.it means I didn't know about it so visiting you. And helping were definit