杜鹃鸟以在其他鸟类的巢中产卵而闻名。

The cuckoo bird is known for laying its ___egg in the nest of other species.

海龟小心翼翼地将卵埋在温暖的沙子里，然后返回大海。

The turtle carefully buried its ___eggs in the warm sand before returning to the ocean.

我们观察了附着在树叶背面的蝴蝶卵。

We observed the butterfly's ___egg attached to the underside of a leaf.