____, the meeting began.

[Ngoc Hoa]

Can you please help me with this question?
Choose the best answer to complete the following sentence:
____________, the meeting began.
A. After we have sat down
B. All of us having taken the seats
C. Our having seated
D. Once we had seated
The key says the answer is B, but I have no idea why. Can you explain this confusing structure for me please?

 

[emsr2d2]

We will be able to help you when you tell us where you found this multiple choice exercise. We need the title of the book and the name(s) of the author(s) or a link to the website. You must do this every time you quote someone else's words. It's a legal requirement of the forum.

 

[Ngoc Hoa]

It would be very nice if you can help me.
The exercise is in Tuyển tập đề thi Olympic 20/4 lần thứ XXIV - 2018 Tiếng Anh, written by Ban tổ chức kì thi
I can provide you with the exact section in the book, but not until later, because I don't have the book with me right now.

 

[5jj]

All are incorrect. B would be OK as All of us having taken our seats

 

[kttlt]

All are incorrect.

Would D be correct as Once we had sat (down)?

 

[5jj]

Yes.