Answer:
It is the second day of Jonas's training as the Receiver of Memory. He has been instructed not to share his dreams with others, but he is still uneasy with the idea that it is permissible for him to lie.
Explanation:
An appositive phrase gives you an alternative description or more information about a noun, and it is separated from other elements in the sentence by commas.
The appositive phrase in this sentence is "a whiz at foreign languages" - you can identify it because it is describing and giving you more information about Mr. Wilson (the proper noun the phrase is next to) and has commas around it.