Question

Now there’s a system _________ the waste is disposed of using the principles of ecology.

A．when

B．which

C．that

D．where

Answer 1

D

试题分析：句意：现在有个系统利用生态学原理处理废物。这句话用了定语从句，先行词是a system，定语从句中不缺主宾表，缺少的是地点状语in the system，所以用where引导定语从句，选D。