It be the vocabulary that caused you the problem in the exercise because you know a lot of words.
The Three Gorges will offer you a wonderful trip, ______ you’ll remember all your life.
Making _______ good impression on the interviewers is of ________ vital importance.
--- You have not lost your heart, then? --- ________. I will try again.
Opposite the old town is the 5500 meters Yulong Xueshan Mountain, its peak_______ with snow.
John opened the door. There_______ he had never seen before.