`=>` Chi asked her mother if they would spend their holiday the next/following month in Ninh Binh.

`-` Câu tường thuật gián tiếp (Yes/No qu-):

S `+` asked `+` O/wanted to know/wondered `+` if/whether `+` S `+` V (lùi thì)

`-` Câu trực tiếp dùng 'will' `->` Câu gián tiếp dùng 'would'

`-` Ngoài ra:

`+` we `->` they, our `->` their

`+` next month `->` the next/following month

 Chi asked her mother if they would spend their holiday the following month in Ninh Binh.

- Cấu trúc câu tường thuật dạng Yes/No: S + asked + if/whether + S + V.

- Lùi thì: will → would.

- Đổi ngôi: we - our → they - their.

- Lưu ý: the next month = the following month.