“is not”的缩写形式是“isn't”。
与not相关的否定缩写：通常在原词后加n't，若原词以n结尾，直接加't。系动词be、助动词、情态动词的否定形式一般可以缩写成为一种简略的形式。如：isnot—isn't、arenot—aren't、wasnot—wasn't、werenot—weren't、hasnot—hasn't、havenot—haven't、willnot—won't、donot—don't、didnot—didn't、usednotto—usedn't/didn'tuseto。
