"These are onions. Do you eat onions?"

Translation: Це цибуля. Ти їси цибулю?

[azurj]

"Це цибуля. Ти їси цибулю?" (the question) is in singular.
"These are onions. Do you eat onions?" (the translation) is given in plural.
Is it right?

[skstudio]

I think the authors wanted to show two things with this task:

1. The constructions "This is ..."/"These are ..." and "It is ..."/"They are ..." are all translated as "Це ..." in Ukrainian.
2. The grammatical number of mass nouns (which can be only plural or only singular) does not always match in English and Ukrainian. For example, "onions" is plural, but its translation "цибуля" is singular; "apples" ("яблука") is plural in both languages; "fruit" is singular, but its translation "фрукти" is plural.

P.S.: Thanks for this very interesting question! These things were not obvious to me until now and I had to do a little research.

[Ken20827]

What is wrong with:
Це цибуля. Ти їси цибулю?

[joseperus]

Just a curiosity. In Spanish, an "onion" is a "cebolla", which sounds pretty similar to "цибуля"

[joseperus]

Seems fine

[zgrrredek]

Can you write just "Їси цибулю?" or "Їсте цибулю?" without "ти" or "ви" in the beginning?

[Federisko]

Yes