The word 'a', 'an' and 'the' are called articles. 'A' and 'an' are called indefinite articles and 'the' is called definite article. They are always followed by a noun or noun phrase. . An article usually contains more information than the basic facts.
In grammer, Transformation is a type of syntactic rule or convention that can move an element from one position to another in a sentence. It is the the rules for transforming one type of sentence into another (affirmative into negative, simple into compound or complex, and so forth).