题目

 Putin will run for president next March in an election that could open the way for him to stay in ______ for 12 more years.    A. power                    B. force                         C. energy                            D. work 答案：A承承同学在“用伏安法测小灯泡的电阻”的实验中，记录数据如下． (1)开关闭合前，滑动变阻器的滑片应移到________，这样做能对电路起 ________作用，在实验过程中滑动变阻器的另一个作用是________． (2)由表中数据可知，三次测得的小灯泡的阻值不相等，原因是：________．