题目

People come into your life for a reason，a season，or a lifetime. When you figure out which one it is，you will know what to do for each person. When someone is in your life for a REASON, it is usually to meet a need you have expected. They have come to help you through a difficulty, to provide you with advice and support. They are there for the reason you need them to be. Then，without any wrong doing on your part，this person will say or do something to bring the relationship to an end. Sometimes they die. Sometimes they walk away. What we must realize is that our need has been me有研究认为，“达菲”的治疗机理是药物与病毒的一种主要表面酶结合，使其不能离开已被感染的宿主细胞。这里的“酶”应是一种 [     ]A．维生素B．糖C．蛋白质D．油脂