Cats are crepuscular, which means they’re most active at dawn and dusk.

猫是黄昏的， 这意味着它们黎明和黄昏最活跃。

It was the first time that sun rays, also known as crepuscular rays, have been viewed so clearly on Mars, said NASA.

美国航天局称，这是第一星上如此清晰地观察到太阳光，也称为黄昏射。

They are usually nocturnal, becoming active at night, but they can also be crepuscular, which means they are active at dawn and dusk.

常是夜行性的，夜间出来活动，但它们黄昏和黎明时分时也很活跃。

These little crepuscular (it means active during twilight) critters will keep you company (and possibly keep you awake) while they play in their cage.

这些小黄昏（这意味着黄昏时活跃）的小动物会笼里玩耍时陪伴您（并可能让您保持清醒）。

There are countless wild species being negatively affected by our light pollution, whether they are nocturnal (active at night) or crepuscular (active during twilight).

有无数野生物种受到我们的光污染的负面影响，无论它们是夜间活动的（夜间活跃）还是黄昏（黄昏时活跃）。