3 sentences

1. 她紧锁着眉头，陷入了沉思。

   tā jǐn​suǒ zhe méi​tóu, xiàn​rù le chén​sī.

   She knitted her brows and fell into deep thought.

   Source: Dong Chinese Dictionary

2. 他紧锁双眉，似乎在思考什么难题。

   tā jǐn​suǒ shuāng méi, sì​hū zài sī​kǎo shén​me nán​tí.

   He knitted his brows, appearing to be thinking about a difficult problem.

   Source: Dong Chinese Dictionary

3. 看到孩子平安归来，他紧锁的眉头终于舒开了。

   kàn​dào hái​zi píng'ān guī​lái, tā jǐn​suǒ de méi​tóu zhōng​yú shū kāi le.

   Seeing his child return home safely, his furrowed brow finally relaxed.

   Source: Dong Chinese Dictionary