energy的形容詞形式是？

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

　　在學習和休息之間保持適當的平衡，能使我們精力充沛。

　　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。