3 sentences

1. 你们一个个都怎么了？

   nǐ​men yī​gè​gè dōu zěn​me le?

   What's wrong with all of you?

   Source: OpenSubtitles

2. 孩子们一个个都穿上了新衣服。

   hái​zi men yī​gè​gè dōu chuān​shang le xīn yī​fu.

   One by one, the children put on their new clothes.

   Source: Dong Chinese Dictionary

3. ‎他们要把我们一个个带去哪里？

   ‎ tā​men yào bǎ wǒ​men yī​gè​gè dài​qu nǎ​lǐ?

   Where are they taking us, one by one?

   Source: OpenSubtitles