at birth的意思是”刚生下来时”“出生时”，看下面的例句：
He weighed six jin at birth.他出生时6斤重。
To some extent, our intelligence is given us at birth.
在某种程度上，我们的智力是生而有之。
at a birth 的意思是“一胎”，例句如下：
There are three kittens at a birth. 一胎生了三只小猫。
单词：birth的近义词、反义词、形近词辨析
birthday/birth/birthplace/born/bear
记忆：
1. bear n. 熊 v. 负担, 忍受, 带给 I can’t bear the smell of the bear. 我不能忍受熊的气味。
2. born adj. 出生的，天生的 He is a born singer. 他是个天才歌手。
3. birth n. 出生 The mother panda gave birth to a .lovely little one yesterday. 昨天那只熊猫生了一只可爱的小宝宝。
4. birthday n. 生日 Thanks a lot for the birthday present you sent me. 非常感谢你送我的生日礼物。
5. birthplace n. 诞生地 It’s natural that old people hope to visit their birthplace. 老人希望回到他们的出生地看看是很自然的。
另类阅读：
Birthday is the day when our mother gives birth to us. Our mother bears us for nearly ten month and then we are born in the birthplace.
轻松一刻
The champion athlete in bed with a cold was told that he had a temperature．
“How high is it，Doctor?” he wanted to know．
“A hundred and one．”
“What's the world's record？”
与单词：birth 相关的例句或者名人名言
The birth of my son was the happiest moment of my life.
宝宝出生的那刻是我这辈子最幸福的时候。
We are happy to announce the birth of our son Andrew.
很高兴地告诉大家我们生了个儿子，取名安德鲁。
The ringing bells proclaimed the birth of the prince.
鸣响的钟声宣布王子诞生了。
We are happy to announce the birth of our son Andrew.
很高兴地告诉大家我们生了个儿子，取名安德鲁。
※There is no cure for birth and death save to enjoy the interval. 生和死都无法治,只有享受两者之间的间隔.
※We should weep for men at their birth and not a t their death. 我们应在人降生时流泪，而不该在人死亡时哭泣。
