What day of the week is it?

今天星期几？

《牛津词典》

But what day of the week was it?

但是，那天是星期几？

youdao

I forgot what day of the week it was.

我忘了今天是星期几了。

youdao

And she asked him what day of the week it was, and he said Friday.

WHITEHOUSE: The White House

As a practical matter, it is difficult to get thirty countries to agree what day of the week it is.

CENTERFORSECURITYPOLICY: Center for Security Policy | Clinton��s CTB And Other Placebos Won��t Stop, Will Compound The Danger Of Proliferating Weapons Of Mass Destruction

Sometimes you only know the day of the week by what's on the menu: Wednesday's curry night, Friday fish and chips, and on Sunday there's a traditional British roast.

BBC: HMS Triumph: Life on board a Royal Navy submarine