I still have a few more doubts.

Question

1) Thank you for being so quick in answering my letter.
2) I wish you all a nice weekend and I look forward to receiving your email.
(Can you help me express these two concepts).

3) Could you start a question with "in between which students is he sitting?"
Is it possible to start a question with "between" and put "in" at the end?
If yes, could you give me an example?
4) Her parents always try to fulfil her wishes.

Answer 1

1) Thank you for replying so soon.

2) OK

3) Could you start a question with "in between which students is he sitting?"
Is it possible to start a question with "between" and put "in" at the end?
If yes, could you give me an example?
Better is to simply omit "in" - it's superfluous!

4) Her parents always try to provide what she wants and needs.