简述园林树木根系的主要功能作用。
参考答案：
1.固定、支撑；
2.吸收水分、养分；
3.回流、合成树体营养物质；
4.保持水土；
5.改良土壤。
单句改错：找出错误的一项并改正。
( )1. Sandy was one of the model at the fashion show. ______
A B C D
( )2. Sandy wore her hair in a 1990's style last Friday. ______
( )3. Miss Hu came into the classroom and the students stopped to talk. ______
( )4. Simon often takes Amy to home and they play the piano together. ______
( )5. There are at least three thousands students in our school. ______
机动车仪表板上（如图所示）一直亮，表示发动机控制系统故障。
