题目

用伏安法测电阻时，待测电阻大约是10欧，电流表的内阻是1欧，电压表的内阻是5千欧，则：（ ）A.用电流表外接法，此时测量值比真实值大      B.用电流表外接法，此时测量值比真实值小C.用电流表内接法，此时测量值比真实值大      D.用电流表内接法，此时测量值比真实值小  答案：B解析:略 38、  What’s the matter with the man hanging his head there? Well, if you _______ know, he was caught stealing my car.    A. must       B. may      C. can      D. shall