第一节：语法和词汇知识（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，并在答题卡上将该项涂黑。
例：It is generally considered unwise to give a child ___________ he or she wants.
A. however B. whatever C. whichever D. whenever
答案是B。
21. Having __________ no-meat day would be a good way of encouraging ___________ low carbon life-style.
A. a; the B. a; a C. the; the D. the; a
22.—Can you give some advice on what I said just now?
—Sorry. My mind______________.
A. is wandering B. was wandering
C. has wandered D. had wandered
