XV.
1. People are very willing to donate to charity.
2. Stop eating sweets at night if you don't want to have a toothache.
3. Dave has been fond of skiing since he moved to Australia.
4. I really enjoy playing musical instruments but I don't have much free time to play.
5. Doing exercise every day is an efficient way to keep fit and avoid diseases.
XVI.
1. He is a big fan of beach volleyball.
2. She is keen on riding a bicycle around the park in the afternoon.
3. My grandfather needs to have a surgery for his heart problem.
4. Lam has taken part in many volunteer campaigns up to now.
5. They have raised funds to help disable children since early 2009.
@Canh