The path down the mountain was slippery. It was hard for us to stay on our feet. 

A. So slippery was the path down the mountain that we found it hard to keep our balance. => đúng

B. So slippery the path down the mountain was that we had difficulty keeping our balance. => sai câu trúc

C. Slipper as the path down the mountain, we had difficulty keeping our balance. => sai cấu trúc + nghĩa

D. Such was the slippery of the path down the mountain that it was hard for us to stay on our feet. => sai cấu trúc 

Tạm dịch: Đường xuống núi trơn trượt. Thật khó để chúng tôi đứng trên đôi chân của mình.

=> A. Con đường xuống núi trơn trượt đến nỗi chúng tôi khó giữ thăng bằng.

Choose A.