Artificial intelligent assistant

What is the meaning of the sentence “You are--aren't you?” in this novel by John Galsworthy? I'm translating a novel by John Galsworthy, _A Stoic,_ written at the beginning of the XX century (full text on Project Gutenberg), and I've come across a sentence I’m finding quite tricky to understand: > You are—aren't you? The context is as follows: > “Sit down. Isn't washing one's head awful?” > Bob Pillin answered feebly: > “Of course, I haven't much experience.” > Her mouth opened. > **“Oh! You are—aren't you?”** The conversation stops here, and that left me without more context to try and grasp the meaning of the question. My guess is that it could be something ironic like “you are experienced in washing your head, aren’t you?”.

I think the sentence refers back to what was said just a little earlier. Phyllis said "Don't be foolish. Sit down. Isn't washing one's head awful?"

So I think when she says "You are--aren't you?" she means to say "You are foolish, aren't you?". She's making fun of his feeble answer. I think it makes sense because she was also making fun of him earlier when he was looking in the mirror and it says "A clear, high, mocking voice said 'Oh-h! Conceited young man!'"

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