How long have you been living here?

(a)  

How long have you been working here?

(a)  

He has been working here for three years already.

(a)  

for instance / for example

(a)  

How long have you been here in Vienna?

(a)  

I have been

(a)  

we have been

(a)  

Where have you been?

(a)  

Where were you?

(a)  

I have been here for three weeks already.

(a)