火花塞（）时，应予更换。
A.绝缘体裙部呈棕褐色
B.火花塞间隙过大
C.中心电极与侧电极有明显损耗
D.火花塞有积炭
参考答案：C
— What are the students ________ about?
— Whether Senior 3 students should join in the coming school sports meet. [ ]
A. quarrelling
B. inspiring
C. fighting
D. arguing
简述话务量控制的策略有哪些？
