We all need regularly.exercise to keep fit

We all need regularly.exercise to keep fit.But if we study all day,we don't have time to run,swim,lift weights,or play basketball.What can we do stay(3).............shape?
One thing we could do is walk(4)...........often.Walking is good exercise.Instead of going to school(5).........car or bus,we could walk.During recess,we could go outside and stroll around before we go back to class.Instead of taking the elevator in buildings all the time,we could use the stairs
Another important thing is to take(6).............from studying.If we sit at our desks or in front of a computer(7)...........a long time,we should stand upand stretch our arms anh legs(8)......each hour.If we stand for a long time,we should sit down and stretch our backs.There are just a(9).......ways we can stay fit when we don't have a lot of time to exercise.Do you know some(10)........ways
3. A.at           B.to              C.in          D.for
4. A.least         B.most             C.less             D.more
5. A.by          B.on             C.in            D.at
6. A.absence           B.exercises           C.marks             D.breaks
7. A.since            B.about               C.for                D.with
8. A.one            B.once              C.none               D.no
9. A.some           B.little           C.few            D.any
10. A.others       B.other            C.another          D.any