医生可以通过研究人类的骨骼学到很多东西。

Doctors can learn a lot from studying human ___bones.

狗把还粘着些肉的骨头埋了起来。

The dog buried the ___bone with some meat still attached.

博物馆展示了一块古老生物的骨骼化石。

The museum displayed the fossilized ___bone of an ancient creature.