Being a parent is not always easy, and being the parent of a child with special needs often carries with _____ extra stress.( ) A. it B. them C. one D. him 答案:A 12.以下是空气污染指数与质量级别、质量状况的对应关系:空气污染指数0~5051~100101~200201~300>300空气质量状况优良轻度污染中度污染重度污染空气质量级别ⅠⅡⅢⅣⅤ根据“中国国家环境监测”数据,2015年10月12日,重庆空气污染指数为99,根据以上信息,判断重庆当天空气质量级别和空气质量状况分别是( )A.Ⅰ级 优B.Ⅱ级 良C.Ⅲ级 轻度污染D.Ⅴ级 重度污染