1.Sally is in high school now.
或：Sally has been in high school for five years now.
楼主此题表达不清楚,sorry!
2.一双运动鞋：a pair of sports shoes 或 a pair of snearkers
3.体操课：(a) gymnastics/gym class
4.clean/tidy (up) the classroom
注：/ 表示可以任意选用其一；（ ）表示可以省略不写.