单选题 The presence of armed guards ______ us from doing anything disruptive.
A. defeated B. irritated C. prevented D. encouraged

【正确答案】 C
【答案解析】(prevent阻止)。句意为：全副武装的卫兵出现了，我们未能做任何破坏性的事情。A．defeat击败；B．irritate激怒，使发炎，D．encourage鼓励。