5 sentences

1. 他低头系衬衫的扣子。

   tā dī​tóu jì chèn​shān de kòu​zi.

   He looked down to button his shirt.

   Source: Dong Chinese Dictionary

2. 他的衬衫掉了一个扣子。

   tā de chèn​shān diào le yī gè kòu​zi.

   A button fell off his shirt.

   Source: Dong Chinese Dictionary

3. 他正忙着扣衬衫的扣子。

   tā zhèng máng zhe kòu chèn​shān de kòu​zi.

   He is busy buttoning his shirt.

   Source: Dong Chinese Dictionary

4. 我扣不上这个扣子。

   wǒ kòu bù shàng zhè gè kòu​zi.

   I can't do this button.

   Source: OpenSubtitles

5. 扣子太小了。

   kòu​zi tài xiǎo le.

   The buttons are too small.

   Source: OpenSubtitles