根据下面要求作文。
        行船有顺流和逆流，人生亦有顺境和逆境。遇上顺境，是人生之幸；但若随波逐流，不思进取，则顺境变逆境。若能敢于逆水行舟——在逆境中勇往直前，则逆境会转化为顺境。
       请以“顺流逆流”为题目，写一篇文章。
      要求：①除诗歌外，文体不限；②文中不得出现真实的姓名和学校名；③思想健康，内容充实，不少于500字。

把下列词语补充完整。

浑然____     完美____

某地农业监测部门统计发现：该地区近几年的生猪收购价格每四个月会重复出现，但生猪养殖成本逐月递增．下表是今年前四个月的统计情况：

现打算从以下两个函数模型：①y=Asin（ωx+φ）+B，（A＞0，ω＞0，﹣π＜φ＜π），

②y=log₂（x+a）+b中选择适当的函数模型，分别来拟合今年生猪收购价格（元/斤）与相应月份之间的函数关系、养殖成本（元/斤）与相应月份之间的函数关系．

（1）请你选择适当的函数模型，分别求出这两个函数解析式；

（2）按照你选定的函数模型，帮助该部门分析一下，今年该地区生猪养殖户在接下来的月份里有没有可能亏损？

阅读理解。

    For years and years people have been saying that railways are dead. “We can do without railways,” people say—as if cars and planes have made railways unnecessary. We all keep hearing that trains are slow, lose money and are dying. But this is far from the truth. In these days of expensive oil, railways have become highly competitive with cars and planes. If you want to carry people or goods from place to place, they are cheaper than planes. And they have much in common with planes. A plane goes in a straight line and so does a railway. What is more, a railway takes you from the heart of a city center. It doesn't stop you as a car does on crowded roads. And no plane or car can ever carry as many goods as one train does.

    Far from being dead, railways are much alive. Modern railway lines give you a comfortable journey. Where else can you eat well, sleep comfortably, feel safe and enjoy the scene while you are traveling at the same time? And we are only the beginning, for we have just entered the age of super-fast trains, which are traveling 150 miles an hour and more. Soon we will be wondering why we spent so much on highways and planes we can't fly in because we don't have enough money to buy the oil.