Translation:It is the mother of six hundred and sixty-two little spiders.
My first try -- It is THE mother of... -- was not accepted. In the correct answer offered, "a" was underlined. I have reported it, because "the mother" sounds more natural than "a mother," though either would be fine on the English side.
Really? Wouldn't it mean that we know about the sipders already? The Czech sentence does not have such a meaning.
Leaving the spiders aside, since my scenario wouldn't work too well in Spider World...
Whether you say "He is THE father of 3 children" or "He is A father of 3 children," you generally mean the same thing: He has or had 3 children. To my US English ear, the version with THE just sounds more natural. But...
Say you and your friend are meeting two guys somewhere. Your friend has told you that one of the guys has 3 children. You're going to be a dad soon, so you want to know which guy has the has kids, so you can talk about how your life is about to totally change and nothing will ever be... Anyway, you ask your friend.
He points to the guy on the right and says, "He is THE father of 3 children." Your friend might also have said "He is A father of 3 children," but using THE is more... definitive, I guess, in this example.
(This isn't exactly a grammarian-level explanation, but I hope it's at least a little helpful...)
Meanwhile, would the Czech sentence have needed a demonstrative in order to be correctly translated as "THE mother"?
"Your friend has told you that one of the guys has 3 children." I thank that is the point. This is not applicable to the Czech sentence here. We do not know about any children yet.
So I think that you would indeed need "To je ta matka" for "the" in the English sentence.
Hmm. I don't understand "We do not know about any children yet." Isn't the sentence telling us about 662 of them? But I DO understand about needing the demonstrative in the Czech sentence for my answer to be accepted, so thanks very much for your help (and your patience)!
I think I was wrong all the time and this is a part of English that deviates from simple rules learned at school (or during my previous work in the UK). I accepted the definite article.
I am in favour of the, not because we know something about the spiders but because these spiders have exactly one mother. It could be different with sister or brother, though somehow the doesn't sound too bad here either.
To echo Renardo's comment - Yes, I think this is the reason we would use the definite article here. Indefinite seems to imply that it's countable and one of many potential mothers. Definite article means that it's unique and there's only one. English grammar books do not do a good job of stressing how this often takes precedence over the rule for using the definite article when we've already been introduced to something.
It must be a nightmare translating (creating) articles when translating from Czech to English.
I would add to the discussion of whether to use the definite or indefinite article here (yes, The mother works better) that even spiders have gender and while “it” is appropriate for spiders we don’t know the gender of, for a mother spider I would definitely use “she.”