Children today have many things to play with. They can watch television, surf ____ Internet, or play video games. But what do you think children ____ (do) for fun long ago? They read books.

    Some of you might ask, "Are books ____ (real) fun?" Believe it or not, books provide many things that television or computers cannot. Since books use only words ____ (tell) a story, they can improve your imagination. You can picture the characters and background in your head and you can also imagine ____ the characters feel.

    The words and sentences that are used in storytelling are also very interesting and usually cannot be found often on television or on websites. They are sometimes so beautiful and touching ____ they can bring tears to your eyes.

    Books also help us to think harder and ____ (deep). As we continue ____(read), we ask questions to ____(our) and try to find answers.

    These are some of the ____(reason) why books are so fun to read.

    Remember: the more you read, the more you grow.

在驰名中外的北京天坛里，有三处堪称奇观的声学建筑：回音壁、三音石和圜丘．当游客在圜丘顶层的天心石上说话时，听到的声音格外响亮，这是建筑师利用声音的反射，使 ____与原声混在一起，声音得到加强造成的音响效果．

2015年8月12日,在天津滨海新区爆炸事故中牺牲的消防官兵6人身份已确认，还有18名官兵失联，66名受伤官兵正在医院救治。这些消防官兵奋不顾身的责任来源于（   ）

①对他人承诺    ②职业的要求

③法律规定       ④传统习俗

为探究不同离子对肠淀粉酶(最适pH为8)活性的影响，某同学开展了相关的实验，其实验步骤和结果见表。请回答：