A.
cut-cutting
cook-cooking
write-writing
sit-sitting
fly-flying
swim-swimming
study-studying
eat-eating
watch-watching
have-having
B.
1) -Are you drinking coffee?
-No, i'm drinking tea.
2) -Are the boys riding their bikes?
-Yes.
3) -Is mum cooking lunch?
-No, she is making sandwiches.
4) -Is Jack going to work?
-Yes.
5) -Are you and your friend doing your homework?
-No, we are watching TV.
6) -Is dad talking on the phone?
-No, he is working in the garden.