题目

某段金属导体，两端电压为6V时，5min内通过它的电荷量是60C，导体的电流是       A；当该导体两端电压降为0V时，电阻为        Ω。  答案：0.2  30解析:略  19. At last he chanced to sail back towards the place _____ he had started.  A. with which B. for which   C. from which       D. on which