It has decided to support selling more energy saving products such as low-energy light bulbs.

VOA: special.2009.07.17

They are very light, that is to say, low mass.

很轻，也就是说，质量很小。

麻省理工公开课 - 固态化学导论课程节选

Absorption is just the opposite of emission, so instead of starting at a high energy level and dropping down, when we absorb light we start low and we absorb energy to bring ourselves up to an n final that's higher.

吸收就是发射的逆过程,与从一个高能量到低能量不同，当吸收光时，我们从低能量开始,吸收能量到一个更高的能量。

麻省理工公开课 - 化学原理课程节选

It has very little light and very low ceilings.

VOA: special.2010.08.04

This is the story of how one man combined LEDs with solar energy technology to bring high-quality, low-cost electric light to poor people around the world.

VOA: standard.2009.12.13