"You are children."
I initially thought -sunuz should be the right ending but checked the word which said çocukturlar, so I thought that must be right, but it was wrong. Lol Watch out, they sometimes try to trip you up. Always think of the correct conjugation as opposed to just writing the word translated as is. ;)
- Sen çocuksun = You are a child.
- Siz çocuksunuz = You are children.
"Sen" can only be used when talking to one person that you are familiar with or is younger than you. So it would be the correct choice if you're talking to one child only.
"Siz" can be respectful singular, but it is also used for ANY groups of people... any age, any familiarity. :-)