crucial 是形容词,意思是关键； 严酷的；极为困难的；极紧要的；决定性的.例：Vitamins are crucial for maintaining good health.维生素是保持身体健康的关键.Teachers are crucial to the success of the school....约等于没说，我是说关于这个单词的句型补充：这是一个典型的虚拟语气。当句子中有crucial, important, necessary 等词做表语时，后面 that 引导的主语从句要用虚拟语气，形式是（should）+动词原型，should 可以省略掉。例：It is crucial that we maintain a healthy life style to live a long life.