there is danger 与 there is dangerous
health 是名词
healthy是 形容词
为什么 要用keep healthy 而不用 keep health
还有就是 there is danger 和 there is dangerous 的区别
级用法
题：Here we shall find how a rabbit tells the other rabbits that there is —
横线那为什么 要用danger 而不用dangerous
我有点混淆,希望 老师们 讲下