secondary light source

例句：

1. 1. The new LED lamp isa more efficient and energy-efficient secondarylight source.
   这款新型LED灯是更高效、节能的次级光源。
2. 2. The researchteam used a secondary light source to studythe effects of light on human behavior.
   研究小组使用次级光源来研究光对人类行为的影响。
3. 3. The secondary light source was usedto illuminate the dark room during the nightshift.
   次级光源被用来在夜班期间照亮黑暗的房间。