puzzle over

She puzzled over the postmark on the letter.

她想弄明白信封上的邮戳。

They puzzled over the question for quite a while.

这问题他们想了很久。

The old general was puzzling over the old map.

老将那旧思索。

He puzzled himself over the matter.

他那件事绞尽脑汁。

I puzzled over the problem for ages before the light suddenly dawned on me.

我这个问题冥思想了很久才豁然开朗。