Translation:The dress that I like more is that black one.
In this case, it is used as a pronoun, and when it is used as a pronoun it only becomes questo / questa / questi / queste
quello = that one (when used as a pronoun)
While "questo" is pretty easy - it is the same as a demonstrative and as a pronoun - quel is a bit different.
"quel" as a demonstrative takes on forms depending on gender and first letter of the following word (for masculine words that would be "quel, quello / quei, quelli"). Used as a pronoun it is much simpler and very similar to "questo" - "quello / quelli" for masculine and "quella / quelle" for feminine.
Could "The dress WHICH I like more is that black one" be an equally correct translation?
Technically, no, not in this context. "That" is a restrictive pronoun. Here's one explanation: https://owl.english.purdue.edu/owl/resource/645/01/
I agree with the comment below as far as formal English is concerned, but also think that "which" would be perfectly acceptable in colloquial English.
By itself, più appears to mean "any more", so di più means "more"
non mi piace più - "I don't like it any more"
mi piace di più - "I like it more"
I don't think that non mi piace di più makes any sense, at least by itself.
I agree with fournier49. Thought I was being clever and put prefer which was marked wrong. Surely it means the same?
I agree with you entirely. I did the same and got marked wrong. But it's perfect English.
Why is "I like that black dress more" wrong. I know it is not literally translated, but it has the same means, and sounds much better in English. Can someone who understand the Italian explain to me why this is wrong?
It just doesn't mean exactly the same thing. The sentence is saying that "Of all the dresses in front of me (or that I own or whatever), I like that black one best." Saying "I like that black dress more" removes the idea of there being a distinct set of options to choose from, instead implying a single other option. It also goes from 'most' to simply 'more'.
Ok, then the correct translation into English should be "I like that black dress (the) best/more". The literal translation word for word sounds strange, I would never say it like that while speaking English. Am I missing something?
What we're both missing is context :P But you're right, "I like that black dress the most" sounds much better as a general rule. There are a few places where it would be natural to say what they do, but not very many.
Piacere doesn't mean "to like", it means "to please". So "mi piace" literally means "it pleases me", and "Il vestito che io piaccio" translates to "The dress that I please" - the dress has no emotions!
Think about it as "mi piace" = "pleases me". I wonder why this isn't accepted as a translation, though -- isn't it idiomatic enough in English? For a thorough explanation see http://blogs.transparent.com/italian/a-different-point-of-view/
"mi piace" is the short-handed form of "piace a me", which you can take as "it is pleasing to me", as ManlyStump points out.
I think "that I prefer" is valid acceptable instead of "that I like more". Reported it.
The problem is that quello is not used as an adjective in this sentence, but rather as a pronoun that means 'that one' ... è quello nero = is that black one
Am I the only one that was shocked when the hint showed "Fascist" as a legitimate translation for "nero"?