Teoria:

Kun kerrotaan että joku asia tai esine ei ole jossain, lisätään lauseeseen not.
 
There is not (isn't) (a cat, a book, a table).
 
There are not (aren't) (many cats, books, tables).
Esimerkki:
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There is not a cat in the room.
There isn't a cat in the room.
 
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There are not children in the classroom.
There aren't children in the classroom.