Keeping a proper balance between study and rest keeps us energetic.

　　在學習和休息之間保持適當?shù)钠胶�，能使我們精力充沛�?/p>

　　We become more energetic, more alert, better able to take effective action.

　　我們變得更有活力、更警覺、更有能力采取有效的行動。

　　You should exercise more so as to keep energetic and you can work efficiently.

　　你應該多運動以保持精力充沛，才可以有效地工作。