Answer:
Mistakenly; completely.
Step-by-step explanation:
A verb is one of the parts of speech in English language. Verbs can be defined as any word that describes an action, occurrence, or state of existence. Some examples of verb are dance, sing, walk, play, run, sit, etc.
An adverb can be defined as a word that is used in English language to modify a verb, adjective, or another adverb. Some examples are slowly, quickly, brightly, sadly, etc.
Generally, adverbs are formed by adding the suffix "ly" to the end of a verb e.g mistake + ly = mistakenly.
Hence, the two adverbs in the sentence "Mr. Gilmore mistakenly turned east at the fork and soon found that he was completely lost." are mistakenly and completely.