Good morning, class!
    We know that there are too many net bars around us. The Internet is popular and it makes our lives colorful. Many of us like going online very much because we can learn how to use the computer and get more information from the Internet. We can learn English. We can read some good newspapers and magazines. It can make us clever in playing computer games. We can send E-mails to our friends quickly. We can chat(聊天) freely online with our friends. It can help us get in touch with people from all over the world.
    But some students spend too much time in playing computer game and some stay in the net bars all day and all night. Teenagers even get to have boyfriends or girlfriends online. They write too many letters to each other. It takes them too much time to chat online so they do worse and worse in their lessons and they don't study well any more. I think we mustn't get online when it is time for us to study. We can do it in summer or winter holidays. We should get online with adults(成人)--our teacher or parents.
    At the same time, if we have lots of free time, we can do some out-of-class activities at school. We usually have activities from 4:50 to 5:50 in the afternoon. We have different kinds of activities. If you are interested in sports, you can play basketball or football. We can go to the English Corner. We can practice talking in English there. We hope we can spend more time on our subjects or on such activities that we can learn a lot from and less time on the Internet.
    Thank you for listening to me. That's all.

海水的综合利用包括很多方面，下图是从海水中通过一系列工艺流程提取产品的流程图。

海水中主要含有Na⁺、K⁺、Mg²⁺、Ca²⁺、Cl^-、Br^-、SO₄^2-、HCO₃^-等离子。

已知：MgCl₂·6H₂O受热生成Mg(OH)Cl和HCl气体等。回答下列问题：

阅读下面两个文言文语段，回答相关问题。
      【甲】元丰六年十月十二日，夜，解衣欲睡，月色入户，欣然起行。念无与乐者，遂至承天寺，寻张怀民。怀民亦未寝，相与步于中庭。庭下如积水空明，水中藻荇交横，盖竹柏影也。何夜无月?何处无竹柏?但少闲人如吾两人者耳。   

                                                                                                                       (选自《记承天寺夜游》)
      【乙】余尝寓居惠州嘉祐寺，纵步^①松风亭下，足力疲乏，思欲就亭止息。望亭宇尚在木末，意谓如何得到?良久忽曰：“此间有甚么歇不得处!”由是如挂钩之鱼，忽得解脱。若人悟此，虽兵阵相接，鼓声如雷霆，进则死敌^②，退则死法^③，当恁么^④时也不妨熟歇^⑤。
                                                                                                                       (选自《东坡志林•记游松风亭》)
       【注】：①纵步：放开脚步，这里指散步。②死敌：死于敌手。③死法：死于军法。④恁么：如此，这样。⑤熟歇：好好地休息一番。

①具有双层膜   ②进行能量转换   ③产生氧气   ④含有DNA   ⑤动、植物细胞都具有．

戊戌变法从开始到失败，历时103天，因此历史上又称它为（    ）