又是安静!黎明前的美妙的时间，就在我的旧书桌前——我从未如此敏锐地认识，如此心怀感激，这些仍旧黑暗的时间。

Peace again! – The exquisite hour before dawn, here at my old desk — seldom have I realized so keenly, appreciated so fully, these still, dark hours.

youdao

例如，如果一只信鸽要用它的太阳罗盘进行导航，它必须根据日光/黑暗的循环所提供的线索正确设置时间。

For instance, if a homing pigeon is to navigate with its Sun compass, its clock must be properly set by cues provided by the daylight/darkness cycle.

youdao

当小龙虾持续被关在黑暗的环境中，即使是4到5个月，它们的复眼仍然可以继续按照日常生活时间，对昼夜视觉进行调节。

When crayfish are kept continuously in the dark, even for four to five months, their compound eyes continue to adjust on a daily schedule for daytime and nighttime vision.

youdao