Page 390 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

iw -
l:l*LtL
(I,) WIH~A~H&F&~~L 5 7~~ 7z0
(That Japanese did not seem to understand English.)
PWPL 49 F
(c) @3C&%&1:!4%&3h7F9 zbl%t&d: < &L7?$ O7Z0
(I seldom drink these days, but I used to drink a lot when I was young.)
1: IfA :
z
(d) ~$z*;;*&%i& 0213&% hao
(In this area there are not people who can speak Japanese.)

1. -nu is an archaic negative marker that corresponds to -nai, but is used
only with verbs. The archaic -nu is used in very stiff written Japanese.
That is why there are quite a few proverbial phrases in which -nu is
used exclusive of -nai.
(1) $22 {&/*&L\l %o&
(Prevention is better than cure. (lit. A cane in advance so as not
to fall.))

(2) %b {&/*&L\l gK
(Ignorance is bliss. (lit. Not to know is to be a Buddha.))
(3) Zb {&/*&L\l 73%
(Better leave it unsaid. (lit. Not to speak is a flower.))
2. There is no past tense form for -nu. See [la] below.

I. -nu is an archaic version of -nai. Except in idiomatic phrases mentioned
in Note 1 -nu can be replaced by -nai, but the reverse is not always the
case.
[I] a. ~0%i&38< I&L\/*&I~
(This book isn't interesting.)

b. @r&&.-x {&LIT / f / *&T / **I:) g@(\{+-.3
t;
7:
(I went to school without eating breakfast.)
-
(e nai de (DBJG: 271-73))