They use specially trained dogs to _____ their sheep at night.

A．take care

B．get along with

C．watch over

D．turn to

下列"骨纤维异常增殖症"描述，哪项不对（）

A.可多同时发病

B.发育成熟后，停止生长

C.可恶变

D.常有病理骨折、畸形

E.好发于骨干，病变较局限