光天化日

night and day───日以继夜地

light and shade───光阴；光与影

light-handedly───轻车熟路

lightmindedly───轻率地

bright and early───adv.一大早

light industry───轻工业

light-mindedly───轻装上阵

Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal clocks.───细胞中的生理节奏时钟对夜间和昼间的光会产生不同的反应，从而使生物体可以根据每天新陈代谢循环的步伐提前应对环境作出调整。

The sun radiates both light and heat every day.───太阳每天发出光和热。