Final answer:
1) big. The adjective in the sentence 'Bob put a big fly on the sharp hook' is 'big'.
Step-by-step explanation:
The adjective in the sentence 'Bob put a big fly on the sharp hook' is big.
An adjective is a word that describes or modifies a noun or pronoun. In this sentence, 'big' is describing the noun 'fly'.
Adjectives can come before or after the noun they are describing. In this case, 'big' comes before the noun 'fly'.
Therefore, the adjective of the sentence is big.