II. 单项填空（共15小题；每小题1分，满分15分）
从A、B、C、D 四个选项中，选出可以填入空白处的最佳选项。
21. The headmaster will ______ a speech to the visiting foreign guests this afternoon.
A. deliver B. address C. announce D. declare
22. Helen always helps her mother even though going to school ______ most of her day.
A. takes up B. makes up C. saves up D. puts up
23. Living in a highly ______ society, you definitely have to arm yourself with as much knowledge as possible.
