第一节 单项填空（共15小题; 每小题1分，满分15分）
请认真阅读下面各题，从题中所给的A、B、C、D四个选项中，选出最佳选项，并在答题卡上将该项涂黑。
21. The driver was at ________ loss when ___________ word came that he was forbidden to drive for speeding.
A. a; / B. a; the C. the; the D. /; /
22. A new system of quality control was __________ to overcome the shortcomings in the firm’s products.
A. invested B. informed C. introduced D. instructed
