单项选择题
A．To warn the reader to stay away from them. B．To compare their voltage to that used in houses. C．To give an example of a living electrical generator. D．To describe a new source of electrical power.
A．1,000. B．800. C．200. D．120.
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.