We spent two days _____ the novel. [ ]
A. read
B. to reading
C. reading
D. to read
答案:C
电力网运行时,()通过电力网就会产生功率损耗。
A.电流
B.感抗
C.电阻
D.电抗
允许速度vmax≤120km/h的客货共线双线铁路,区间两相邻线路直线部分最小线间距离为()。
A.4000mm
B.4200mm
C.4400mm
D.5000mm