puzzle over

She puzzled over the postmark on the letter.

她想弄明白信封上的。

They puzzled over the question for quite a while.

问题他们苦苦地想了很久。

The old general was puzzling over the old map.

老将军着那旧地图苦苦思索着。

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.

个问题冥思苦想了很久才豁然开朗。