have fun doing something 可以
gain fun from doing something
have fun to do something 有点不常见,因为不定式是将来的动作,而这里是 “获得”,是已然的动作,所以,to do 不太常用
have fun doing something 可以
gain fun from doing something
have fun to do something 有点不常见,因为不定式是将来的动作,而这里是 “获得”,是已然的动作,所以,to do 不太常用