Final answer:
The word 'pas' is the correct word to fill in the blank in the sentence 'Elle est pas gentille.'
Step-by-step explanation:
In the sentence 'Elle est pas gentille,' the correct word to fill in the blank is pas. The word 'pas' is a negation adverb in French and is used to negate the verb 'est' in the sentence. It is commonly used in negative sentences to mean 'not.'
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