fertile

他们在肥沃的河流山谷中定居。

They settled in the ___fertile river valleys.

这片地区肥沃的土壤非常适合芦苇生长。

The ___fertile soil in this area is perfect for reeds to grow.

受精的卵可以发育成小鸡。

A ___fertile egg can develop into a chick.