前轮前束值CA141汽车规定为（）mm，EQ140型汽车规定为（）mm，JN150型汽车规定为（）mm。
参考答案：2-4；2-6；6-8
There is reason to believe that most writers have difficulty in ________ the opening paragraphs of
their papers. [ ]
A. constituting
B. constructing
C. comprising
D. founding
环境中常见的二次污染物有
A．SO2和NOx
B．二恶英和甲基汞
C．甲基汞和光化学烟雾
D．NOx和酸雨
E．多环芳烃和二恶英
