C. 1. been standing, been queuing
2. had, broken
3. left, been sitting, noticed
B.1.
Paul, why are your hands so soft?
Because I have been doing the washing-up.
2.
Are the onions ready for the pan?
Yes, Carol has been peeling them/Yes, Carol has peeled them.
3. Rachel, you look tired.
Yes, I have been cutting the grass.
4. Tim, your hands are very cold.
Yes, I have been defrosting the fridge.
5.
Are the floors clean?
Yes, Niel has swept them.
6.
Why are your eyes red, Carol?
Because I have been peeling onions.