I have noticed the same thing. Sometimes the ending sounds like zee, and sometimes it sounds like hee, depending on which exercise it is in. When you play the slow version, it seems it is always pronounced hee, but the word is spelled with a zeta. Is the second zeta here pronounced as a soft ζ or soft γ? Or in Greek is it pronounced both ways and you have a choice?
You make an excellent point but that's not how this works. After a quick search, I found the explanation. If someone with more knowledge on the matter can weigh in (excuse the pun), please do. :)
1) Ζυγίζω needs a complement. A complement is something that has to follow to the verb for it to make sense and the syntax to work. It may be an object, a predicate, a dependent clause.
2) Here, δύο τόνους is not an object, it's an adverbial, because the sentence answers the question Πόσο ζυγίζει ο ελέφαντας; For the transitive version, the question would be What is the elephant weighing?
In Ο ελέφαντας ζυγίζει δυο τόνους, τόνους is in ackusative because is the direct object (answers the question what does the elephant weigh, just like in I gave her 10 books 10 books answers what I gave and not how many.
Τόνους is in accusative and simply cannot be an adverb because it does not end in -ως ή -α.
weigh vi have a given weight ζυγίζω ρ μ
These apples weigh almost a pound.
As far as I can tell, δύο τόνους is not an object but an adverbial complement. Also, if someone can decipher the specifics that answer the question at p.24 that are relevant to this exercise, please let us know. 'What does the elephant weigh' takes an object, e.g. a barrel, but what does 'How much does the elephant weigh' take? Δύο τόνους functions like an adverb: - Πόσο ζυγίζει; - Τόσο/Πολύ/Λίγο/Ελάχιστα/Καθόλου/Τρία κιλά/Δύο τόνους. 'Object' cannot be the answer.
There is no real reason, I believe, because there is no room for confusion. Greeks don't even know the existance of other kinds of tons. So, if you want to refer to any kind of ton in greek, you will just say τόνος. We don't differentiate them, 'cause we don't use them. Ton is a unit of measure and we differentiate it, when confusion is possible. Confusion is not possible in that case.
Yes, but confusion is possible in English. Therefore, to preserve the lack of ambiguity, it should be translated as tonnes or perhaps metric tons. Translating it as simply tons is inferior since it introduces ambiguity into the English version that, as you pointed out, is not present in the Greek.