已知x=$\sqrt{2}-1$，y=$\sqrt{2}+1$，求$\frac{x^2-2xy+y^2}{x^2-y^2}$的值．

下列各项中与所给数据最接近的是（ ）

根据下列句子及所给汉语注释，在句子空缺处写出各单词的正确形式 。
⑴Thomas Edison ____ (发明) the light bulbs.
⑵He went into the room ____ (慢地) and sat down.
⑶You can't solve the problems____ (除非) you do it carefully.
⑷He has a kind____ (心) and often helps others.
⑸Some animals, for example, elephants and koalas, live on grass and ____ (树叶)
⑹My uncle bought me an Ipad for my ____ (第十二) birthday.
⑺So far, we've____ (成功) in saving thousands of people in danger.