2 sentences

1. 他们正在挖一个洞。

   tā​men zhèng​zài wā yī​ge dòng.

   They're digging a hole.

   Source: Tatoeba

2. 他挖了一个深洞。

   tā wā le yī​ge shēn dòng.

   He dug a deep hole.

   Source: AI Challenger 2017