单项选择题
A．Electric eels are potentially dangerous. B．Biology and electricity appear to be closely related. C．People would be at a loss without electricity. D．Scientists still have much to discover about electricity.
A．refrigerated food item may go bad B．traffic lights do not work C．people must rely on candlelight D．elevators and escalators do not function
A．Disobedience. B．Laziness. C．Lack of intelligence. D．Vanity.