"He is naturally a nice boy."
If this is not acceptable (I can't say I'm 100% sure), how come Google translate has never heard of it?! In fact, they don't use c'est even as an alternative and they're correct most of the time in the case of simple sentences.
"Il est" should be a correct answer for "he is", and should be accepted alongside "C'est"
http://french.about.com/library/weekly/aa032500.htm Modified noun
Hahaha! I love how I literally said and recorded Duolingo's recording of the exact phrase verbatim before this question, then I typed it out just as I said it, and it was marked as wrong. It's like a bad teacher. :-P
Most adjectives in French are put after the noun, but some are usually placed before them (such as gentil, jeune, bon, jolie, beau etc.). Some adjectives can be put either before or after the noun, often with slight variations in meaning (for example "ancien" which means "former" before and "old" after the noun). Some more information here: http://www.french-linguistics.co.uk/grammar/adjectives_position.shtml http://french.about.com/od/grammar/a/adjectives_4.htm
Interesting page. Thanks.
In terms of this specific example, though, I still don't get why "gentil" comes before and "sympa" comes after when they both mean essentially the same thing. Or is it simply that "gentil" is a more commonly used word?
It's one of those things you just have to learn. It has nothing to do with their meaning really, it's just rules (except for the words that can be placed both before and after).
It really should be an option to write "Il est", and annoying to get it wrong, when it would appear that it is acceptable.