---Great changes in our hometown since ten years ago.
| A．have happen | B．have taken place | C．happened | D．have been taken place |
It’s important _______ us __________English well.
A. of, learning B. for, to learn C. of, to learn
I spent three hours_____ this book.
A. finish reading
B. to finish reading
C. finishing reading
——What are you doing _______ vacation?
A. to B. for C. at
You have a ___ . You should stop eating anything.
A. headacheB. Backache C. stomachache
——______ do you go camping?
——Once a month.
A. How long B. How often. C. How many.