________ seems to be a strong competition in China for senior high students to enter universities does exist in other countries as well.
She was putting on her watch when the _____ broke and it fell to the ground.
Psychological studies show that some people are quick-tempered _____.
The _____ stuck on the outside of the envelope said "By Air".
It was the largest experiment we had ever had; it _____ six hours.
I have been looking for this book for months, and _____ I have found it.