题目

D         In only six days I lost seven pounds of weight. Two full inches in the first three days!      These are the kinds of statements used in magazine, newspaper, radio and television ads, promising new shapes and new looks to those who buy the medicine or the device. The promoters of products say they can shape the legs, slim the face, smooth wrinkles, or in some other way to add to beauty or desirability.      Often such products are nothing more than money-making things for their promoters. The results they produce are questionable and some are dangerous to health.  � 一个伏特计，量程为3伏，当它串联一个6千欧电阻去测一个3伏电源时，示数为1.0伏，那么这个伏特计的内电阻为________欧．用这个伏特计接入图所示电路中测R1两端电压，读数为1.5伏，此时毫安计读数为2毫安，那么R1电阻大小为________欧