A. Who is the greatest person you know and why?

The greatest person I know is King Sejong because he made Hangul.

A. Who is the greatest person you know and why?

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B. Are you okay? / Are you all right? ✔

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No, I am sick. ✔​(Punctuation)

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That's so bad.

=> Corrected : The sentence is corrected grammatically. 

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That's too bad.​ 

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