二氧化硫的排放量主要受燃烧方式、锅炉运行情况和煤的（）等因素影响。
参考答案：性质
机动车上高速公路，以下哪种说法是正确的？
A、可在匝道、加速车道、减速车道上超车B、不准倒车、逆行、穿越中央分隔带掉头C、非紧急情况时可在应急车道行驶D、可以试车或学习驾驶
Jim did very well. He ________ two goals before half-time. [ ]
A. had scored
B. had kicked
C. scored
D. made
