某课外学习小组想描绘标有“4V、2W”的小灯泡的U﹣I图象，除导线和开关外还备有以下器材：

A、电流表（量程0.6A，内阻为1Ω）   B、电流表（量程3.0A，内阻为0.6Ω）

C、电压表（量程5.0V，内阻为5kΩ）  D、电压表（量程15V，内阻为10kΩ）

E、滑动变阻器（最大阻值为5Ω，额定电流1.0A）

F、滑动变阻器（最大阻值为2kΩ，额定电流0.2A）

G、电源（电动势为6.0V，内阻约为1.5Ω）、导线若干

阅读下面短文, 按照句子结构的语法性和上下文连贯的要求, 在空格处填入一个适当的词或使用括号中词语的正确形式填空。

      About the importance of health, nobody can explain ____ (well) than your doctor. They are the people who really know the importance of keeping fit and healthy. Every time I put on ____ extra pound, my doctor will remind me about what is happening ____ my body. We may look healthy but we don't know ____ (clear) what is happening inside. And there are many different ways we can make sure that we are as ____ (health) inside as we are outside. The first and easiest step is keeping a good ____ balanced diet. Next is sleeping well. Sleep early. Make sure you get your nine hours' sleep. Do not skip your breakfast. It is one of the most important ____ (meal) of the day. Exercise every day. Go for a swim, or walk, or just play football or tennis. Try your best not to have too much stress because it''s very ____ (harm) to your health. Remember to keep ____ (wash) your hands, and then you won't catch any infections(传染病). And getting away from your bad habits ____ (be) important too.

目前有关部门做出决定，司机酒后驾车会受到严惩。交警常用一种“酒精检测仪”检查司机是否酒后驾车。其反应原理为C₂H₅OH+4CrO₃+6H₂SO₄═2X+2CO₂↑+9H₂O，反应中红色的CrO₃转变为绿色的化合物X，则X的化学式为 （   ）