Tag Questions

[Bnplbnpl]

Hello Alan,

Would you please help me with the following sentences which I doubt about?

1) I think Eric is willing to help, don’t I?
2) I don’t think Eric is willing to help, do I?
3) I wish to buy a new piano, don’t I?
4) She wishes she can have a new dress, doesn’t she? 

According to the relevant basic rules, I would say the above tag questions are correct. However, sentence nos.1 & 2 seem weird to me somehow. I’m wondering if the tags should be “isn’t he” and “is he” respectively. As for sentence nos.3 & 4, I was told the tags should be “may I ” and “may she” which I’ve really got no idea whether they are correct or not.

I’d be grateful if you would get back to me at your earliest convenience.

Best wishes,
bnplbnpl

[Alan]

No, your tags are technically quite correct.

To make it sound more natural, however, yet maintain grammatical correctness, we would simply split the sentence into two, e.g.

I think Eric is willing to help. Isn't he?