60659
I was taking a n5 grammar test and I came across the question:

> あの人{ひと} は有名{ゆうめい} ＿＿＿＿

The answer I chose was くなかった. However, the quiz said the correct answer was
ではありません. Why is that?
CC BY-SA 4.0
2018-08-03T19:53:29.243
60658
2018-08-03T22:26:20.973
2018-08-03T20:59:15.803
1628
29804
question
grammar adjectives jlpt i-adjectives na-adjectives
Why is くなかった wrong and ではありません preferred in this sentence?
有名 is a _na_ -adjective and thus is followed by だ・で・な・に (or by じゃ < では)

> あの人は有名だ  
>  _lit._ that person is famous
>
> あの人は有名な人だ  
>  _lit._ that person is a famous person
>
> あの人はきっと有名になる  
>  _lit._ that person is surely going to become famous

You can think of ではありません or じゃありません as the negative of です (which in turn is
the polite form of だ whose negative would be ではない or じゃない). Hence

> あの人は有名 **ではありません**  
>  _lit._ that person **is not** famous

The point of the question seems to be to test your ability in identifying _i_
- and _na_ -adjectives correctly as well as inflecting these adjectives. One
cheap way of recognizing _i_ -adjectives is by their dictionary form, which
always ends in an _okurigana_ い (like 速い、寒い、安い、…). Here 有名 does **not**
inflect like an _i_ -adjective. Of course, _i_ -adjectives would inflect like

> あの人は速 **くなかった**  
>  _lit._ that person **was not** fast

where くなかった is the ending you chose. Here 速い _hayai_ means "fast" (note the い
as _okurigana_ ).
CC BY-SA 4.0
2018-08-03T20:58:09.710
60659
2018-08-03T22:26:20.973
2020-06-17T08:18:27.500
-1
1628
60658
answer