Kenji, Ms. Brown, and 'Do You Mind?'
During lunch, Ms. Brown, the ALT, is holding a tray and asks Kenji, 'Do you mind if I sit here?' Kenji wants to be polite, so he says, 'Yes, please.' Ms. Brown looks surprised for a moment, then sits down. After she leaves, Kenji's friend says, 'You told her she couldn't sit there.' Kenji is confused. He has studied English for three years and knows that 'Yes, please' is a polite answer when someone offers something. Earlier that day, a shop clerk asked, 'Would you like a bag?' and Kenji answered, 'Yes, please,' correctly. Now he thinks the same answer should work for Ms. Brown's question. He asks you to explain the difference between the two questions.
1. Explain why 'Yes, please' was appropriate for the clerk but not for Ms. Brown.
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The clerk's question, 'Would you like a bag?', is an offer. 'Yes' means 'I want the bag', and 'please' makes it polite. Ms. Brown's question, 'Do you mind if I sit here?', asks whether her sitting there would bother Kenji. 'Yes' means 'I mind' - that is, 'I do not want you to sit here'. So the same word 'yes' points in opposite directions in the two questions. Kenji intended 'Please sit down', but Ms. Brown heard 'I object'.
2. What should Kenji have said? Give two natural answers with different levels of formality.
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A simple, polite answer is: 'No, not at all. Please sit down.' A more casual answer is: 'Of course not - go ahead.' Both answer the mind-question negatively, meaning 'It does not bother me', and then invite her to sit. The key is to answer 'No' to 'Do you mind...?' when giving permission, and to add an invitation so the meaning is clear.
3. If Kenji really did not want anyone to sit there, what could he say politely without answering 'Yes' to the mind-question?
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He could say: 'I'm sorry, but I'm saving this seat for a friend.' This is polite because it gives a reason and avoids a direct 'Yes, I mind', which can sound harsh. It also does not answer the negative question in a way that could be misunderstood. In English, refusing an offer or request often uses 'I'm sorry, but...' plus a reason.