Is is not abbreviated as is n, t, which is a very common form of English expression. Because it contains is, it belongs to be verb, followed by negative word not. Just add a comma to everything, but you should pay attention to many points in the abbreviation form. It's very puzzling. Many students only remember a certain rule, not all sentences are applicable, so we should pay special attention to this and not take it for granted. There are some special formats to remember. For example, in English, this is not abbreviated and cannot be written as thisn, t, which is definitely inseparable. The abbreviations of these three words are, was and has. For example, the abbreviations of it is, it was and it has are all it's. Many people will make mistakes in this special situation, so students must be aware of this when using it, and abbreviations cannot be used in simple oral answers.