题目

阅读理解 Everyone needs friends. We all like to feel close to someone. It is nice to have a friend to talk, laugh, and do things with. Surely, there are times when we need to be alone. We don't always want people around. But we will feel lonely if we never have a friend. Sometimes friends move away. Then we feel very sad. We miss them very much. But we can call them and write to them. It could be that we would even see them again. And we can make new friends. It is surprising to find out how much we like new people when we get to know them. No two people are the same. Sometimes friends don某同学测绘标有“3.8v 0.4A”小灯泡的伏安特性曲线，提供的实验器材有：A．电源（4V，内阻约0.4Ω）B．电压表V（2V，内阻为2kΩ）C．电流表A（0.6A，内阻约0.3Ω）D．滑动变阻器R （0～10Ω）E．三个定值电阻（R1=lkΩ，R2=2kΩ，R3=5kΩ）F．开关及导线若干该同学研究后发现，电压表的量程不能满足实验要求，为了完成测量，他将电压表进行了改装．在给定的定值电阻中选用（选填“R1”、“R2”或“R3”）与电压表（选填“串联”或“并联”），完成改装．