And, even more pressing, how on earth does one know whether "Are" in "Are un kilolitru de apa" refers to "it" (the suggested solution), "he", or "she"? How do you know from the sentence who the "are" refers to? I do not believe that such a construct is possible in English, for example. It would be translated to "has a kilolitru of beer", right? The information on the person is completely missing from that.
Hope it makes sense what I say