题目

完形填空 （共15题，每小题2分，共30分） My best friend is Cocoa, and I live in a senior-citizen apartment. Cocoa is a ten-year-old dog and I am a sixty-nine-year-old lady, so you can see we both qualify as   11  citizens.  He is a   12  companion. He does many amusing things that make me  13  , and when that happens, he is so delighted  14  he just keeps it up.  But one afternoon, Cocoa started acting strangely. I was sitting on the floor playing with him,  15  he started pawing and smelling at the right side of my  16  . He had never done anything like this ever已知x和y满足约束条件 则的取值范围为________．