单项选择题
A．birds are important in our lives B．animals are important in our lives C．nature is important in our lives D．Audubon was especially interested in birds
A．The earth. B．Birds. C．Scientists. D．The natur
A．Colds are always very dangerous. B．Colds are often unpleasant though not dangerous. C．Actually nothing can help get rid of colds. D．The best way to keep colds away is to be healthy.