问题
选择题
There is a system ________the waste is disposed of using the principles of ecology.
A．which
B．where
C．that
D．at which
答案
答案：B
题目分析：考查定语从句：句意：现在有个系统利用生态学原理处理废物。先行词是a system，定语从句中缺少地点状语，用where引导定语从句，D选项如果是in，也是对的，选B。
能与
或水反应生成氧气