题目

--- Take a seat，Anna. _____ and help yourself to anything you like. --- OK，thanks. A. Take your time              B. It doesn’t matter C. Make yourself at home        D. Don't worry 答案：C 按照国III标准车辆比国II标准可大幅度削减单车的污染物排放，其尾气排放量比国II标准的车辆至少减少30%．据统计：我国按照国II标准每年汽车尾气的排放量大约在1.2亿吨左右，那么按照国III标准每年汽车尾气排放量用科学记数法表示为A.3.6×1010KgB.8.4×1010KgC.3.6×1011KgD.8.4×1011Kg