76 CHAPTER 2. VERB GRAMMARbases form
( )( )This helper verb is used in combination with verbs in their ,
so that the polite form of becomes + , and the polite negative is
formed by taking this and making negative using the super
classical negative ” ”: +. While the explanation might be more
complicated than you might have expected, the final result should sound
familiar, since the polite negation - , and the general statement
, are used constantly in modern Japanese.
With this, we can form the polite past tense for / :
, or more formally,
”This is a book.””This is not a book.””This is not a book.”Past negativeFor , the present negative ( ) is placed in past tense,
turning into : ( ).”This was a book.””This was not a book.””This was not a book.”For , things get really weird: the in
( ) is placed in past tense, which involves adding the past