单选题
Without the help of people from every corner of the world, people in Wenchuan County, Sichuan Province ______ recovered very quickly from the May twelfth Earthquake.
【正确答案】
B
【答案解析】 考查虚拟语气。句意为：“如果没有各国的援助，四川汶川的人们不可能很快从5·12大地震中恢复过来。”couldn't have done意为“不可能做某事”。