题目

—Is that the small town you often refer to? —Right, just the one _____ you know I used to work for years. A. that       B. which     C. where       D. what 答案：C 解析: 略点燃下列气体不可能发生爆炸的是（　　）A、天然气和空气B、沼气和空气C、氢气和甲烷D、一氧化碳和空气