Give this memory test a try. Mix up 52 playing cards. Now look at the top seven for a second. Can you remember them in order?
Players at the World Memory Championships can. In fact, the 2002 champion (冠军), Andi, memorized the order of 1196 cards after looking at them for only an hour! And a German girl, Lara, only ten years old, memorized 75 faces and names in fifteen minutes!
    In 1987, a Japanese man, Mr. Tomoyori, wanted to prove that his memory was the best in the world by remembering by heart pi (π), a number in math which starts 3.14159…This number never repeats itself or ends. He recited pi to 40,000 decimal places (小数位). It took the fifty-five-year-old man more than twelve hours to say the numbers, but he did it without making a mistake!
      To remember pi, Mr. Tomoyori connected each number with a sound. He then made up stories to help him remember the words he made from the sounds. In an interview after his achievement, he said, “I decided to go ahead and memorize the value of pi up to one thousand places. But it wasn't easy – in fact, it took me three years. To get to 40,000 decimal places it took me about ten years.”
    Unluckily for Mr. Tomoyori, his record was broken in 1995, when another Japanese man, Mr. Goto, memorized pi to 42,195 places.

用配方法解方程x²+4x+1=0时，经过配方，得到（　　）

材料1：

材料2：小月在非洲旅游时，沿途依次观赏到如下景观：狮子在草原上追逐动物；大象在雨林中悠闲地戏水；长颈鹿在啃食树上的叶子；骆驼队在沙漠中行走。

材料3：非洲小朋友妮比的日记摘录：“我的家乡在一个偏僻的山村，村庄北面是连绵的山地，覆盖着茂密的原始热带雨林。一条河流发源于北部山地，蜿蜒从西绕村庄向东南流去。村庄东面有一片水塘，周围是大面积的可可种植园，我们村和全国各地一样，其他农作物很少，主要依靠出售可可的钱购买粮食和日用生活品……”

下列标点符号使用正确的一项是（　　　）。