3 sentences

1. 他是我们这组的头儿。

   tā shì wǒ​men zhè zǔ de tóu​r.

   He is the head of our group.

   Source: Dong Chinese Dictionary

2. 他是头儿。

   tā shì tóu​r.

   He's the boss.

   Source: OpenSubtitles

3. 这支铅笔的头儿削得很尖。

   zhè zhī qiān​bǐ de tóu​r xuē de hěn jiān.

   The tip of this pencil is sharpened to a point.

   Source: Dong Chinese Dictionary