单项选择题
A．a very great English novel B．an accurate portrayal of life in wartime C．an excellent piece of satire D．the work of a neglected author
A．is insignificant B．is enormous C．seems overestimated D．remains unknown
A．it protects him against the harmful rays from space B．it provides sufficient light for plant growth C．it supplies the heat necessary for human survival D．it screens off the falling meteors