阅读下列材料：

材料一 打破藩界，重划全国行政区。全国划为3府72县，由中央政府任命府、县知事管理，完全取消大名的封建领主权。大名离开藩国，迁居东京，从国家禽俸禄。

——初中世界历史教学用书资料

材料二

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根据材料内容，选择正确答案。

    Hi, boys and girls! My name is Gina. I'm an assistant at Mr. Miller's Store. Now let me say something about the store. On the first floor (层), we sell clothes for girls. The skirts in white, red, black and yellow are only $35. We have socks in all colors. They're only $8 for two pairs. How much are our sweaters? Only $25!

    If you are a boy, you can go to the second floor. Look at those baseball hats. Do you like them? They are only $6. Are you very fat? We have some big jackets for you. They are $40. We have some shorts, too. They are only $18.

    What do you need? Come to Mr. Miller's Store now!

木兰代父从军的勇敢决定，使她成为一位家喻户晓的巾帼英雄；鲁迅弃医从文的明智决定，使他成为一位国人敬仰的文坛巨匠；邓稼先毅然回国的果断决定，使他成为一位人民称颂的“两弹”元勋……人的一生需要作出许多决定，但无论怎样的决定，对我们都是一种考验，我们也一定会从中得到有益的启示。

请以“一次难忘的决定”为题，写一篇不少于600字的记叙文。

要求：①抒写真情实感（诗歌除外）。②文章中不得出现真实的校名和人名。

为了探究声音音调与频率高低的关系，小明设计了如图所示的几个实验。你认为能够完成这个探究目的的是(   )