My students are from Mexico.
My students are from Ukraine.
My students are from Congo.
My students are from a number of different countries.
So that's who your students are. Your students are many different nationalities, though now they're ____?_____ .
I want to know who your students are.
Okay, I can tell you who my students are. My students are from many different countries.
Here's something that might be helpful:
Wh Questions and words for students and teachers of English grammar
The "grammar" used with wh- questions depends on whether the topic being asked about is the "subject" or "predicate" of a sentence. For the subject pattern, simply replace the person or thing being asked about with the appropriate wh-word.
- (Someone has my baseball.) Who has my baseball?
- (Something is bothering you.) What is bothering you?