单项选择题
A．Fire can help people in many ways. B．Fire can be both helpful and dangerous. C．Fire can burn things and people. D．We must be careful with matches.
A．will die B．will warm our houses C．might burn us D．will help us
A．We know how people began to use fire. B．Nobody knows how to make a fire. C．It was an Australian who started a fire. D．We are not sure how people started a fir