Liu Mei has a h____family. She lives w____．her grandparents and parents in Dantu. Her father is a doctor. He goes to work o____．foot every day. He is not very tall, b____．he is very strong. Her mother is a teacher. She goes to work by car. She often h____．her students at school. Liu Mei's grandparents stay at home. In the morning, they go t____．the park. In the afternoon, they d____． tea with their friends. In the e____,they watch TV .Liu Mei is a student in No.1Middle School. Her school is beautiful. There are many tall b____．there. She wants to s____everyone around her school. She likes it very much.

已知点P（x,y)在不等式组$\left\{\begin{array}{c}x-2\le 0\\ y-1\le 0\\ x+2y-2\ge 0\end{array}\begin{array}{c}\\ \end{array}\right.$表示的平面区域上运动，则z=x-y的取值范围是　(     )