我在后院种了一棵桑树，夏天会结出甜美的果实。

I planted a ___mulberry in my backyard that produces sweet fruits in summer.

爷爷的老骡子每天都会帮他驮运柴火。

Grandpa's old ___mule carries firewood for him every day.

他们闻到房间里有霉味。

They smelled ___mold in the room.