Considering the fact that the negative form of verbs normally is made by adding a negative element, this article tries to find out whether this element is the only sign of negating the sentences, and if any affirmative sentence has necessarily a negative correspondent. In this research, through adopting a descriptive-analytical method and based on the ideas of the two functionalists named Givon and Miestamo, the negative forms of some affirmative sentences will be studied. Since the affirmative and negative sentences have different presuppositions, contexts, and discourses, it is not always enough to make negatives just by adding a negative element, and also the act of making the sentence negative might cause some other changes to the sentence. Moreover, it can be said that in Farsi, it is not always possible for an affirmative sentence to have a negative form.
)