4. a.Has she seen a spider? Yes, she has.
b.Has she been studying for the exam? Yes , she has.
c. How long have you been knowing Jack? I have been knowing him for 3 months.
d. Has he been winning many medals?
Yes, he has.
e. Have they been dancing for two hours? Yes, they have.
5.
1. b
2. a
3. b
4. b
5. b
6. c