relief是可数名词吗

　　The next crew relief comes on duty at 9 o'clock.

　　下一批换班的员工9点钟接班。

　　Their differences have been thrown into sharp relief by the present crisis.

　　目前的危机使得他们的分歧更加引人注目。

　　It was a relief to be able to talk to someone about it.

　　能和别人谈谈这件事，感到舒心多了。