Oh, how long has it been since I have seen one!

我有多久没有看见苹果流啊！

youdao

How long has it been since you heard from your parents?

自从你收到你父母来信有多长时间了？

youdao

How long has it been since you've heard from your daughter?

从你上次接到你女儿的信以来有多长时间了？

youdao

How long has it been since I rode a horse?

NEWYORKER: The Insufferable Gaucho

Memory loss can be a factor, and they may not realize how long it has been since their last bath.

CNN: Is bathing just once a week healthy?