What the adverb that modifies the adverb in the sentence. She drives very gracefully.

"Very" is an adverb that modifies the adverb "gracefully." It tells how gracefully she drives.

The adverb that modifies the adverb in the sentence "She drives very gracefully" is "very," which modifies the adverb "gracefully."

To determine this, you can follow these steps:
1. Identify the adverb in the sentence. In this case, the adverb is "gracefully," which describes how she drives.
2. Look for other adverbs in the sentence that modify the adverb. In this case, the adverb "very" is modifying the adverb "gracefully." It intensifies the meaning or degree of "gracefully," emphasizing the level or extent of how gracefully she drives.

By recognizing and understanding the role of each adverb in the sentence, you can determine which adverb modifies another adverb.