A:CH3﹣CH=CH2与
B: 与
C:甲苯和二甲苯
D:CH2═CH﹣CH═CH2和CH﹣CH2﹣CH2﹣C≡CH
下列计算错误的是( )
物理兴趣小组的同学们想探究通过导体的电流与电压的关系.实验室有:电源、电压表、电流表、滑动变阻器、规格不同的定值电阻、开关和导线等器材各若干供同学们选择,实验用电路如图a所示.
—Someone helps you when you are in trouble. What should you say to them?
—I say “________” to them.