2021银行校园招聘考试：英语单选题（3）
Economics, several courses of which I have taken thus far, ______ to be difficult but useful for almost all students。（ ）
A. prove
B. proves
C. have been proved
D. are proved
东吴教育参考答案解析
答案:B
解析：考查主谓一致。其中several courses of which I have taken thus far为设置的干扰项。由于主语为表示学科的单数名词，故谓语应是单数形式。prove to be证明是，主动表被动。
