人体中内环境稳态所包含的内容不包括

若$\left\{\begin{array}{c}x=-2\\ y=1\end{array}\right.$是方程组$\left\{\begin{array}{c}mx+ny=1\\ nx+my=7\end{array}\right.$的解，则（m+n）（n﹣m）的值为（　　）

There's ___________ football under the teacher's desk. Let's play ___________ football, OK?

阅读下面的一段话，判断正误。

    Hi! I'm John. Come here, my friends! Look at my dog. It has two big eyes. It's very cute. This is my cat, Mimi. It's fat. It's two years old. I have six fish. Oh! Mimi likes(喜欢) my fish. I have a bird, Polly. It's beautiful!