Past Perfect Continuous or Present Perfect Continuous?

Quite a simple exercise this. I'm pretty sure I've got all these right, but not too sure to post my answers here! If anybody could make corrections I would be grateful for your time. Thanks, Matt.

1. Chris had been working for ten hours when he fell asleep. 1- Past Perfect Continuous
2. Have you ever had the feeling that you’re being followed? 2- Neither
3. Amy has been swimming since she was young. 3- Present Perfect Continuous
4. When the company went bust, I’d been working there for five years. 4- Past Perfect Continuous
5. Mark has been desperately trying to finish his novel. 5- Present Perfect Continuous
6. He had almost completed his novel when he suddenly had an idea for a short story. 6- Neither
7. Mark has been eating fatty food and chocolate since his return to England. 7- Present Perfect Continuous
8. When I arrived, they’d been waiting for twenty minutes. 8- Past Perfect Continuous
9. Stop shouting so loudly. You are drawing attention to yourself. 9- Neither
10. I’ve been fighting this cold for a week now. 10- Present Perfect Continuous
11. The government has been keeping UFOs secret since the incident at Roswell. 11- Present Perfect Continuous
12. My sister’s been giving up smoking for years now. 12- Present Perfect Continuous
13. What happens to Maximus Decimus Meridius at the end of Gladiator? 13- Neither
14. Before the police turned up, the people had been rioting for two hours. 14- Past Perfect Continuous
15. When I saw the girl walking into the café last night, I could have sworn that I’d met her before. 15- Neither