1条染色体含有1个双链的DNA分子，那么，1个四分体中含有（  ）

    Spring in Nanjing is very short .It is warm and sunny .People (人们) like to go to the parks on sunny days . It is very hot in summer in Nanjing .People do not like to play balls in the afternoon .They like to go swimming in summer . In autumn , it is cool and sunny. Many people like to come to Nanjing in autumn .In winter , it is cold in Nanjing .Boys and girls like to make snowmen and go skating . They have great fun in winter .

该图中的4条河流均位于我国境内，据此完成问题。

河流名称与图序相符的是(    )

塘栖枇粑是全国享有盛名的杭州特产，其果型美观，肉柔软多汁，甜酸适口，风味较佳。为了获得优质果实，须用科学的繁殖和管理方法。请分析以下内容：

下列各句中“而”的意义和用法，与例句相同的一项是（    ）

例：吾尝终日而思矣