3 sentences

1. 窦先生是我们的新老师。

   Dòu xiān​sheng shì wǒ​men de xīn lǎo​shī.

   Mr. Dou is our new teacher.

   Source: Dong Chinese Dictionary

2. 鼻窦炎会引起剧烈的头痛。

   bí dòu yán huì yǐn​qǐ jù​liè de tóu​tòng.

   Sinusitis can cause severe headaches.

   Source: Dong Chinese Dictionary

3. 他从墙上的狗窦钻了进去。

   tā cóng qiáng shàng de gǒu dòu zuān le jìn​qù.

   He crawled in through the dog hole in the wall.

   Source: Dong Chinese Dictionary