boat是可数名词还是不可数名词

　　例句：

　　His eye lit upon a small boat on the horizon.

　　他无意中看见地平线上有一条小船。

　　The boat was going under fast.

　　小船正迅速下沉。

　　He had a new car and a boat.

　　他有一辆新车和一条船。