energy 做不可数名词时意为" 活力，干劲，精力，能源”比如：Its a waste of time and energy.

energy 有复数形式 意为" 精力，力量”比如；creative energies 创造力。

相关介绍

In the exam there's sure to be a question on energy.

考试时准有关于能量的题目。

It's a waste of time and energy.

那是浪费时间和精力。

He has carried out extensive research into renewable energy sources.

他已经对再生能源进行了广泛研究。