他的生日是什么时候用英语怎么说

"When is his birthday?" in English can be translated as "What is the date of his birthday?"

The phrase "birthday" comes from the Old English word "geburh-dæg" which means "the day of a person's birth."

Example Sentences in English:

Can you remind me when his birthday is?
I would like to send a birthday card, do you know when his birthday falls on?

Translations in Chinese:

你能提醒我他的生日是什么时候吗？
我想送他一张生日卡，你知道他的生日是什么时候吗？