第31题: [单项选择]They failed to ______ the directors that their proposals would work, therefore all of their work is just a waste of time and effort. A. convince B. confirm C. convert D. control 参考答案:A 答案解析:题意是:他们没能______领导者其计划行得通,所以他们所有的工作都不过是浪费时间和精力。[A]convince“使确信,说服”,convince sb that...“使某人确信…”,符合题意。[B