Once I spent ten days in Saddlestring Wyoming, riding at dawn and dusk until my backside was incredibly sore.

有一次，我在怀俄明州的 Saddlestring 待了十天，黎明和黄昏都骑马，直到我的背部变得非常痛。

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

猫是黄昏的， 这意味着它们在黎明和黄昏最活跃。

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

狮子通常是夜行性的，在夜间出来活动，但它们在黄昏和黎明时分时也很活跃。

They are most active at dawn and dusk, munching  on a variety of grasses and small plants.

它们在黎明和黄昏时最活跃，咀嚼各种草和小植物。

The researchers concluded that early mammals may have had the ability to see in twilight—the lower light conditions that happen at dawn and dusk.

研究人员得出结论，早期哺乳动物可能有在暮光下看到东西的能力——黎明和黄昏时发生的光线较弱的情况。