Question

【题目】Now there is a system the waste is disposed of using the principles of ecology.

A. when B. that

C. where D. what

Answer 1

【答案】C

【解析】考查定语从句。句意：现在这有一套体系：废物可以使用生态的原则被处理掉。a system是先行词，它在定语从句中做抽象的地点状语，因此选C。