Rewrite the following sentences based on the given words.
1.He is crazy about beach volleyball.
》He is ............................(fan)
2.What she fancy doing is to ride a bicycle around the park in the afternoon.
》She is ...........................(keen)
3.My grandfather needs to have a surgery. His heart problem is very serious.
》 My grandfather ....................(for)
4.Lam has participated in many volunteer campaigns up to now.
》Lam ................................(part)