which 引导的是定语从句,修饰 amounts of food.如果正常语序的话 应该是 they(animals) convert which( amounts of food) to thick layer of fat.谢谢您的回答，这句话可以写成Almost all animals that hibernate prepare for hibernation during summer by eating large amounts of food to which they convert thick layers of fat.吗？当然我们可以把to 提到which前面，但是一般不这样写，因为convert sth to sth是个固定结构，如果提前to的话容易引起歧义。