Who

hsiaoyunhCan I say:

Who are eating my cake now? NO These kids are!

Who is eating my cake now? YES These kids are!

What if the speaker has already known that there are more than one eating his/her cake?

Is the question still the same as "Who is ..."?

I think I'm confused if who is always single no matter what the number of people it represents is.

Thank you in advance.

When forming a question with the "Who" as the subject, generally use "is."

Who is coming to the party?

Who is in that crowd of people?

If you have a predicate nominative in the plural, then you can use "are."

Who are those people? Who is that person?
Who are the parents of this boy? Who is this boy's mother?
Who are the inv

hsiaoyunhWhat if the speaker has already known that there are more than one eating his/her cake?

Is the question still the same as "Who is ..."?

Yes. It's still Who is ...?
The choice between Who is/was ? and Who are/were ? is actually very simple.
Use Who are/were? only when a plural noun phrase follows.

Plus, it's logical to use "is" .
From the first moment you make the question, you cannot imagine (or you don't expect) more than 1 person eating your cake...
And you can't start the question by asking
"who ARE those people eating my cake" because it's easier to think that just a single person is eating your cake.

Or when you ask "Who is at home" u don't say "who ar

If you want to find out the members who are online, you will have to click on "Who's online?" Notice that it is not "Who're on line?"