Here are the answers:
14. A: "HAS your father got a football?" B: "No, HE HASN'T."
15. A: "HAS your mum got a computer?" B: "No, SHE HASN'T."
16. A: "HAVE you got a drink?" B: "Yes, I HAVE."
17. A: "HAVE the girls got new coats?" B: "No, THEY HAVEN'T."
18. A: "HAS John got a sister?" B: "Yes, HE HAS."