~(na)no desu/da
~(na)n desu/da
~(na) no
All mean the same thing. 'n' being a couropution of 'no.'
(so, obviously, 'no da' is very uncommon outside of test-books and the likes)
What they do is imply more information, or possibly or like 'because'.
For example:
A Japanese looks at you funny becasue your white.
In explaning why your there, ryuu-gaku sei nan desu would be natural.
It means:
(the reason I'm here is) I'm studing abroad.
In a situation like that, ~(na)n desu is the most natural.
I went to Japan.
Sou? Doko ni itta-n desu ka?
Where did you go (I want to know more!)?
Remember not to touch the structue in Japanese.
e.g>>A good reply would be ~ ni itta-n desu.
(I posted this awhile ago...)
怖くないです is wrong as you can't have です after a negative いadjective.


o:o
That cannot be true...Yahoo:
Results 1 - 10 of about 41,800,000 for じゃないです
Results 1 - 10 of about 1,180,000 for よくないです
Results 1 - 10 of about 314,000 for 怖くないです