The watch's battery is worn down.

电池没电了。

1 battery 电池

replace the battery

更换电池

The battery is flat.

电池没电了。

a battery of..

一系列；一批；一大群

He faced a battery of questions.

他面临一系列问题。

2 worn down 磨损不堪的；疲惫不堪的..

My heels of my shoes have worn down.

我的鞋跟磨损了。

worn out

疲惫的

After the race,he is worn out.

赛后，他疲惫不堪。

A:What can I do for you?

有什么可以帮您的？

B:Yes.There is something wrong with my watch.It stopped several hours ago.

是的。我的表坏了。几个小时前它不走了。

A:Let me have a look.The watch's battery is worn down.

让我看看。电池没电了。

B:How much is a battery?

一个电池多少钱？

A:50 dollars.

50美元。

B:How long will it last?

能用多长时间？

A:About 2 years.

大约两年。