what is the mistake?

[Unregistered]

Please tell me what is the mistake in this exchange:

"Is John ill? He's lost a lot of weight."
"Yes, he is rather slender these days, isn't he?"


Is it the comma after "days"? Can you expain your answer to me?

Thank you.

Rebecca

[Tdol]

It's 'slender', which is a positive word. Try 'thin'.