我们明天必须在天刚亮时就出发去机场。

We have to leave for the airport at ___the ___crack ___of ___dawn tomorrow.

农民们常常在破晓时分就开始工作。

Farmers often start their work at ___the ___crack ___of ___dawn.

黎明时分是去森林里观鸟的最佳时间。

___The ___crack ___of ___dawn is the best time for birdwatching in the forest.