She'd been up at the crack of dusk knocking on our door.
问题描述：
She'd been up at the crack of dusk knocking on our door.
答
她从天快黑的时候就开始敲咱家门了.
"The crack of dusk",是说天快要黑的时候.另一个词组"crack of dawn"（天快亮时）用的比较多一些.