A:Because he wants to watch the game.
B:Because he wants to help other people.
C:Because he wants to be a guide.
解:∵AB=2cm,BC=2AB,
∴BC=4cm.
∴AC=AB+____=____cm.
∵D是AC的中点,
∴AD= 12 ____=____cm.
∴BD=AD﹣____=____cm.
如图所示,电源电压为10V,R′的最大电阻值是R的3倍,滑片P在b点时电流表的示数比P在ab中点时减小了0.1A,那么R的值为( )
关于文学常识和名著阅读表述不正确的一项是( )
有关下列区域的叙述,不正确的是( )