单项选择题
A．burning fossil fuels to make electricity is widely used B．wind power is a widespread way to make electricity C．energy problems will soon be solved D．nuclear energy will solve all the energy problems we are facing
A．only nicotine leads to cancer B．few people will get cancer C．"light" cigarettes make people healthy D．other chemicals besides nicotine cause cancer
A．is one time zone B．is divided into five time zones C．is divided into twenty-four time zones D．cannot be crossed in five days