请同学任意写出一个经过点（2，-1），且y随x增大而减小的一次函数的解析式：______．

用所给词的正确形式填空

1. ________ (who)radio is this?

2. There are five _______(novel) on the desk.

3. ________ (they)classroom is big, but _______ (our) is small.

4. They have a cat._______ (it) name is Mimi.

5. These CDs are ________ (Ben).They are not ________ (Kitty).