A. When was the last time you went to the zoo?

Maybe when  I was in 5th grade.

=> Corrected : The sentence is corrected grammatically. 

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B. Simsoon, is this your wallet?

Is this your wallet, Simsoon? ​(Punctuation)

No, it isn't. My wallet is green. ​(Punctuation)

Jo, is this your wallet? ​(Punctuation)

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