贾珊的回答：

世界人口在以每年八千万的幅度增长 The world population is growing at a rate of eighty million a year. 世界人口在以每年八千万的幅度增长 The world population is growing at a rate of eighty million a year.

郑 传的回答：

世界人口在以每年八千万的幅度增长 The world population is growing at a rate of eighty million a year. 世界人口在以每年八千万的幅度增长 The world population is growing at a rate of eighty million a year.