题目

如果一个种群的密度愈来愈小，下列选项中与之无关的是（    ） A．种群处于衰退期 B．种群内雄性趋于不育 C．种群死亡率超过出生率 D．群落结构太复杂 答案：D15．What does the woman mean？  A．It is unfair that the man's wife should stay at home．  B．it is impossible to repair the pipes again．  C．It is not the first time that the pipes leaked．