二次函数y＝ax²＋bx＋c的图象如图所示，则下列判断中错误的是 (     )

读东南亚地区图，回答问题．

问题提出：如图①，将一张直角三角形纸片$△$ABC折叠，使点A与点C重合，这时DE为折痕，$△$CBE为等腰三角形；再继续将纸片沿$△$CBE的对称轴EF折叠，这时得到了两个完全重合的矩形（其中一个是原直角三角形的内接矩形，另一个是拼合成的无缝隙、无重叠的矩形），我们称这样两个矩形为“叠加矩形”.

知识运用：
（1）如图②，正方形网格中的$△$ABC能折叠成“叠加矩形”吗？如果能，请在图②中画出折痕；
（2）如图③，在正方形网格中，以给定的BC为一边，画出一个斜三角形ABC，使其顶点A在格点上，且$△$ABC折成的“叠加矩形”为正方形；
（3）若一个锐角三角形所折成的“叠加矩形”为正方形，那么它必须满足的条件是什么？结合图③，说明理由。
拓展应用：
（4）如果一个四边形一定能折成"叠加矩形",那么它必须满足的条件是什么？

根据短文理解，选择正确答案。

    “Cool” is a word with many meanings. Its old meaning is used to express a temperature that is a little bit cold. As the world has changed, the word has had many different meanings. “Cool” can be used to express feelings of interest in almost everything.

    When you see a famous car in the street, maybe you will say. “It's cool.” You May think, “He's so cool,” when you see your favorite football player.

    We all maximize(扩大)the meaning of “cool”. You can use it instead of many words, such as “new” or “surprising”. Here's an interesting story we can use to show the way the word is used. A teacher asked her student to write about the waterfall(瀑布) they had visited. On the student's paper was just the one sentence, “It's so cool.” Maybe he thought it was the best way to show what he saw and felt.

    But the story also shows a scarcity(缺乏)of words. Without “cool”, some people have no words to show the same meaning. So it is quite important to keep some credibility(可信度).Can you think of many other words that make your life as colorful as the word “cool”? I can. And I think they are also very cool.