life是不可数名词，为什么还有复数形式、

life泛指“生命”时是不可数名词;泛指“性命”时是可数名词;泛指“生活”时是不可数名词,其前不加冠词,但指某种有比较具体内容的“生活”“生活方式”时则是可数名词。for life的意思是“一辈子,一生”,当所指的人为复数时,也可以用复数形式for lives。

life   

英 [laɪf]   美 [laɪf]  

n.  生活，生计; 生命，性命; 一生，寿命; 人生，尘世;

变形 复数: lives

拓展资料

双语例句

1. No matter where you go in life or how old you get, there's always something new to learn about. After all, life is full of surprises.  

不管你生活在哪里，你有多少岁，总有新东西要学习，毕竟，生活总是充满惊喜。

2. If you love life, life will love you back.  

热爱生活，生活也会厚爱你。

3. When life gets hard and you want to give up, remember that life is full of ups and downs, and without the downs, the ups would mean nothing.  

当生活很艰难，你想要放弃的时候，请记住，生活充满了起起落落，如果没有低谷，那站在高处也失去了意义。

4. The happiest are not those who own all the best things, but those who can appreciate the beauty of life.  

最幸福的人们并不一定什么都是最好，只是他们懂得欣赏生活的美好。

5. If you're not satisfied with the life you're living, don't just complain. Do something about it. 

对于现况的不满，不能只是抱怨，要有勇气作出改变。

6. A journalist all his life, he's now brought out a book.  

他当了一辈子新闻记者，如今已出了一本书。

life作“生命”解时，是可数名词，复数为lives，作“生活”之意是不可数名词。
如：
The steadfast work and happy life

　　踏实工作 快乐生活

Life is like a journey, no matter what the destination, but the scenery along the way and the mood at the view

　　人生就象一次旅行,不必在乎目的地,在乎的是沿途的风景以及看风景的心情

Three lives were lost (ie Three people died) in the accident.

　　事故中三人丧生.

There is no life on the moon.

　　月球上没有生物。
建议参考http://baike.baidu.com/view/98321.htm

life是个名词，意思有很多
下面是life的所有意思
1.生命;生存[U]
How did life begin?
生命是如何起源的?
2.生物,活的东西[U]
There is no life on the moon.
月球上没有生物。
3.(个人的)性命[C]
He risked his life to save the child.
他冒生命危险救那孩子。
4.一生;寿命[C]
His life was full of misfortunes.
他的一生充满了不幸。
5.(物的)寿命,有效期[C]
The machine's life is very long.
这机器使用寿命很长。
6.人生;世上[U]
Life isn't all fun.
人生不都是充满欢笑。
7.生活(状态);生计[C][U]
I know that he has a very hard life.
我知道他日子过得很艰难。
He did not know her way of life.
他不知道她的生活方式。
8.传记[C]
I'm reading the life of Dickens.
我在读狄更斯的传记。
9.元气,活力[U]
He is full of life.
他充满了活力。
10.支柱,灵魂[the S][(+of)]
She was the life of the party.
她是宴会上最活跃的人。
11.无期徒刑[U]
The criminal was sentenced to life.
罪犯被判处无期徒刑。
12.实物,真货[U]
This was painted from life.
这是根据实物画的。

当他表示生命，生物时，是可数名词，复数形式为lives，其他意思如表示人生，寿命时是不可数名词，总之，判断其是可数还是不可数，必须在具体的语境中体会出来

life 在表示"生命、生活“时，用复数形式

表示一个个的生命的时候是可数的。
比如说他们的生命 their lives are equally precious as ours.