题目

如果一个种群的密度越来越小，最可能的原因是（）      A．种群处于衰退期    B．  种群内雄性多于雌性      C．种群死亡率超过10%    D． 种群结构太复杂 答案：A从以下方框内选出适当的句子，完成对话。 Tom：What are you going to do after leaving school? Bill：I’m thanking about becoming a plane driver．  1    Tom：So you like traveling，don’t you? Bill：Of course I do．I like to visit different places，make different friends and know different things． Tom：That sounds good．  2   Bill：What do you want to be in the future? Tom：  3  I like to go into business and make money． Bill：  4   Tom：You’re fight．  5  Bill：Yes．I agree with you．    A．Business people are very busy，you know． B．I like planes very much． C．That way I would be able to travel to New York． D．But I’m always thinking “busy” is better than “free”． E．I’ve changed my idea now． F．Maybe I’ll be a businessman． G．But I would rather live in one place．