birthday是可数名词；birthday n.生日；复数： birthdays；
例句：
What can I get him for a birthday present?
我给他送点什么生日礼物呢？
It isnt just any day ─ its my birthday!
今天不是一般的日子——是我的生日！
Here's a little something for your birthday.
这是送给你的生日小礼物。
I completely forgot her birthday, what with one thing and another.
因为忙得不可开交，我把她的生日忘得一干二净。
We're getting up a party for her birthday.
我们正在筹备她的生日聚会。
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