下列关于人体的结构层次描述正确是（    ）

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$\sum _{n=1}^{2015}\frac{1}{n\left(n+1\right)}$=____ 

下列句子中，加横线的成语使用不恰当的一项是（    ）

信息传递在生态系统中具有重要作用．下列各种信息中，属于行为信息的是（ ）

先通读下面的短文，掌握其大意，然后从A、B、C、D四个选项中选择可以填入空白处的最佳答案。

    Everyone likes holidays,because they can do what they want to．The May Day holiday is coming.The students in1class are making the holiday plans.Here are2of them．

    Li Darning，the monitor of my class，is going to have a3with his parents in the city park．He says many people would like to go to the park4May Day．He can help clean the park after5picnic．Wang Lingling always works hard．She's going to have a rest at home first and then see her grandparents．Zhao Dan6he's going to Beijing to visit the Summer Palace and the Great Wall．He thinks it'll be busy7good fun．As for me．I'm going to enjoy8too．I'm going to Qingdao to9my holiday．Qingdao is a coastal(沿海的)city．There's a lot to see and to do there．I think I can have a good time there．

    What's your10for the coming May Day holiday?