No. "those" is another word that doesn't show up in the romanian. this would be completely in the proper context: 'Hey, there are some huge fish over on this side of the boat! come look!" "are they sharks? You know I'm a shark fanatic!"
Actually, "those" in Romanian would be "acei" or "aceia" but that would be more specific like "those sharks over there."
It sounds kind of weird but "Aceia sunt rechini?" would be "Are those sharks?"
"Acei rechini sunt bolnavi." = "Those sharks are sick."
The pronunciation of the plural sounds exactly like the singular form or am I mistaking?
Yes, the plural, with the "i" at the end is pretty much impossible for me to discern too. However, since "sunt" is the third person PLURAL I know it is plural.