energy名词形式
energy本身就是一个名词，意思是能量，
例如
1.The system produced enough energy to heat several thousand homes.系统产生的能量足以给几千户人家来供暖。
2.In the exam there's sure to be a question on energy.考试时准有关于能量的题目。
3.It's a waste of time and energy.那是浪费时间和精力。
energy本身就是一个名词，意思是能量，
例如
1.The system produced enough energy to heat several thousand homes.系统产生的能量足以给几千户人家来供暖。
2.In the exam there's sure to be a question on energy.考试时准有关于能量的题目。
3.It's a waste of time and energy.那是浪费时间和精力。