读一读：式子“1+2+3+4+…+100”表示从1开始的100个连续自然数的和，由于式子比较长，书写不方便，为了简便起见，我们将其表示为$\sum _{n=1}^{100}$n，这里“∑”是求和符号，通过以上材料的阅读，计算$\sum _{n=1}^{2015}\frac{1}{n\left(n+1\right)}$=____ 

阅读《舍得》，完成下面小题。

       ①著名作家贾平凹说：“会活的人，或者说取得成功的人，其实懂得了两个字——舍得。”舍得，《现代汉语词典》解释为“愿意割舍，不吝惜”，实际意思偏向于“舍”。贾平凹的话是在告诉我们：要学会舍。

       ②舍能体现一个人的智慧。

       ③现实世界纷繁复杂，我们常常面临着舍的考验，需要我们不断地去选择，去割舍。当无法同时完成许多事情时，当感到“心有余而力不足”时，我们就一定要舍，该舍就舍，是智慧的体现。2007年，“阿里巴巴”董事局主席马云面对旗下淘宝网是否收费问题时，他的分析是：“阿里巴巴”的长远目标是成为中国最好的电子商务平台，目前的主要任务是做大规模;同一时间既想做大规模，又想赚大钱，现有能力还做不到。因此，马云最终决定不收费。马云是睿智的，他的舍是为了更大的发展，是为了走得更远。如今，“阿里巴巴”已成为中国最好的电子商务平台。

       ④舍能体现一个人的品德。

       ⑤列夫·托尔斯泰在《一个人需要多少土地》中写了这样一件事：面对“用脚丈量多少土地就可得到多少土地”的诱惑，帕霍姆长时间不停地用脚丈量土地，最终吐血而死。帕霍姆的贪得无厌是造成这一悲剧的真正原因。

       ⑥陶渊明不为“五斗米”折腰，远离混浊的官场，回归田园。他舍去对名利的追求，体现了淡泊名利的品德，是一种很高的人生境界。

       ⑦学会舍，我们能拥有人生的智慧，获得成功;学会舍，我们能不被物欲所迷、名利所惑、世俗所左右，就能活得高尚，活得坦荡。

       ⑧请记住泰戈尔的名言：“当鸟翼系上了黄金，就再也飞不远了。”

19世纪中叶，日本爱国志士认为要救国必须推翻(    )

阅读下面短文，从短文后所给的A、B、C、D四个选项中， 选出可以填入空白处的最佳选项

    “It's nice having a friend,” said Mole (鼹鼠) to Rabbit as they sat talking in the sun one day.

    “Oh, it is!” said Rabbit.“Very useful, too, 1 if you need help. 2, I think I'd like Bull(公牛) to be my friend.”

    “But I'm your friend!” said Mole, feeling 3.

    “Oh, yes,” said Rabbit.“You are good for talking to and laughing with, 4you are too small. When I need help, I 5 someone big and strong like Bull.He would be a very good friend to have. It would be 6 shouting for him when I need help.”

    Mole went off in anger.

    “Oh，well，I need to 7 something,” Rabbit thought.

    He moved along 8 he found a tiny garden.He had just started on his first leaf when there was a big 9. People were shouting and dogs were barking(吠叫).Rabbit was so afraid and in such a 10 to get away that he ran into the wrong hole.

    The hole was too 11 and Rabbit got stuck(被卡住).He could not 12 at all.

    “Help!” cried Rabbit.

    Mole 13 him.He ran up to see what was the matter.

    “Help!” cried Rabbit.“I'm stuck in this hole.”

    “If you want help,” said Mole，“I'd better 14 Bull.”

    “No!” cried Rabbit.“He's no good! He's too big to get into this 15.You're just the right 16! Please help me，Mole!”

    So Mole began digging around Rabbit.He 17 so fast that Rabbit was 18 soon.

    “I'm sorry, Mole.I was 19,” Rabbit said.“I'm 20 I have you for a friend.” And so the two good friends set off for home together.