题目

中国传统农业的主要耕作方式是 A．耜耕 B．石器锄耕 C．火耕 D．铁犁牛耕 答案：D 解析: 略The children, ________ had played the whole day long, were worn out. A. all of what           B. all of which         C. all of them           D. all of whom