单项选择题
A．why people neglect their health B．what people know about health C．when to provide health education D．who is more likely to become ill
A．no day really has twenty-four hours B．the earth is divided into time zones C．time zones are not all the same size D．no one knows where time zones begin
A．The Importance of Electricity B．The Pollution of Making Electricity from Fossil Fuels C．The Advantage of Using Nuclear Energy D．Means of Making Electrical Power