grass可數嗎？

　　例句：

　　1. I let the horse drop his head to crop the spring grass.

　　我讓馬低下頭啃吃春天的青草。

　　2. The windows overlooked a lawn of tall waving grass.

　　窗戶外邊是一塊草地，高高的草隨風搖擺。

　　3. Mr Zuma had a solid reputation as a grass roots organiser.

　　作為一個民眾的組織者，祖瑪先生名聲甚佳。