—My parents don't want me to watch TV on school nights. What should I do?
—Well, you _________ talk with them, but you must finish your homework first.
A:shall
B:could
C:can't
D:mustn't
下列事件中,是必然事件的为( )
有两个灯泡,L1标有“6V3W”的字样,L2没有标记,测得L2电阻为6Ω,把它们串联在电路中,两灯均正常发光,那么该电路两端电压和L2的电功率分别是( )