题目

演替是一个漫长的过程，当群落演替到与环境条件处于平衡状态时，演替就不再进行了，此时所达到的最终平衡状态就叫顶极群落，顶极群落主要由平均温度和年降水量决定。以下对顶极群落的理解有误的是         ( )。 A．群落演替的终点是顶级群落 B．若没有外力干扰，顶极群落将保持相对稳定状态 C．达到顶级群落时的生态系统比演替早期时的恢复力稳定性强 D．形成哪种顶级群落主要取决于气候条件 句型转换（共10个空，每空0.5分，分） 小题1: Going to sleep early is important for the teenagers. __________  _________  _________  for the teenagers to go to sleep early.小题2: You should read more English books. You  ________  _________ read more English books.小题3:He had to stay up late last night because he hadn’t recited NCE.(改为否定句) He ________  _________  _________ stay up late last night because he had recited NCE.小题4: If it doesn’t rain tomorrow, we will climb Baiyun Hills. We will climb Baiyun Hills _________ it _________ tomorrow.