单项填空
从A、B、C、D四个选项中，选出可以填入空白处的正确答案，并在答题纸上将该项涂黑。
21. This book tells ____ life story of John Smith, who left ____ school and worked for a
newspaper at the age of 16.
A. the；/ B. a；the C. the；the D. a；/
22. — Will $ 1,000 _____ the cost of the trip?
— I’m afraid not. Perhaps I need _____ $ 400.
A. pay; another B. charge; more
C. cover; another D. afford; more
23. — How can I prepare for class, Mr. Johnson?
