第二部分:知识运用(共两节, 满分35分) 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。 It is believed that ______ European chemist called Felix Hoffmann first produced ASA which completely changed ______ man’s understanding of aspirin. A. an; a B. the; a C. a; / D. an; /