Page 654 - Makino,Tsutusi.DictionaryOfIntermediateJGrammar

580 wake ga nai

Qm
Wake ga nai basically negates either (a) the existence of a reason to believe
that someone will do / does something, will be /is in some state, or some-
thing will happen / happens, or (b) a possibility of someone's future / present
action or state, or a future / present event. Thus, sentences before wake ga
nai are always nonpast. However, wake ga nai can indirectly negate the
existence of a reason to believe that someone did something or was in
some state, or that something happened, or negate the possibility of a past
action or state by presenting the negation in a statement about a common
belief, a habitual action or state, or one's ability. For example, KS(B) can
be used in a context as in (1).
(1) A: FY-I~XP~~TH~S~TXP-L~:F~~:L,
(I heard that Charles mastered Japanese in a year.)

B: W~ES E~*:~~+/~QCZB< TXP-&%Z,~C~#~~\,
j,
(=KS(BN
(You are kidding! It is impossible to be able to master Japanese
that quickly.)
e elated ~xpressionl

However, hazu ga nai can be used with past sentences and it negates the pos-
sibility of a past action, state, or event, as in [2]. (See Note.)
[2] a. %Ekis.+/tQZ29Lf. {lt%/???;blfI #&L\,
(It is impossible for her to have done such a thing.)
YPI i.ttLl
b. %E~@b&fiTtZ ICtT/???;bCfl #*L\,
(It is impossible for him to have been an excellent student.)