stone可数还是不可数

　　例句：

　　The stone steps were worn and broken.

　　这些石头台阶被磨平破裂了。

　　The stone struck her on the forehead.

　　石头击中她的额头。

　　A large stone landed right beside him.

　　一大块石头正好落在他身旁。

　　Most of the houses are built of stone.

　　这些房子多数是用石头建造的。