【单选题】How long have the people known each other?
【单选题】听力原文:W: How long have you known Susan? M: I've known her about three years. I met her in the library where we used to read, but now I can only see her on the campus occasionally. Where did Susan often...
【单选题】______ have you known the city? For five years. [ ]
【判断题】由于水利工程建设项目经济评价采用的数据,大多数来自预测或者估算结果,其效益、费用和计算期等都存在着一定程度的不确定性。
【单选题】决 定化学反应速率的主要因素是反应物的性质,影响反应速率的因素有 、 、 温度、催化剂等.