第17题: [单项选择]College students in this city have set up "the Cleaner Air Society" to help urban citizens become aware of the _________ to our environment. A. conditions B. situations C. dangers D. threats 参考答案:D 答案解析:考点 单词辨析题。四个选项可以分为两组,每组中两个词在词义上非常接近,区别甚微。 conditions“存在的环境”;situation“形势,局势,局面,情况,境遇,处境”;danger“危险,危