单项选择题
A．how an undersea 'volcano broke out B．how an island rose up in the sea C．how soil was formed on a new island D．how life began on a volcano- produced island
A.not many B.serious problem C.bits of waste things D.industrial pollution
A.Cutting out unnecessary buying. B.Eating less. C.Reducing excess use. D.Carefully disposing of our daily products.