2 sentences

1. 我看他愁眉苦脸，忖他一定遇到了困难。

   wǒ kàn tā chóu​méi​kǔ​liǎn, cǔn tā yī​dìng yù​dào le kùn​nan.

   Seeing his long face, I reckoned he must have run into difficulties.

   Source: Dong Chinese Dictionary

2. 这事到底该不该做，他一个人忖了很久。

   zhèi shì dào​dǐ gāi bù gāi zuò, tā yī gè rén cǔn le hěn jiǔ.

   He pondered for a long time by himself whether or not he should do this.

   Source: Dong Chinese Dictionary