トミー、今日は一日、何して遊んだの?
Tommy, how did you spend your play day today?

 どろんこ遊びしたの。
I played in the mud.

 道理で泥だらけなわけね…
No wonder you're covered with mud.

 あらー! あの子、泥の上に座っちゃってるー!
Oh, no! He's sitting in [on] the mud.