单选题 The towers of a suspension bridge serve as a rigid framework to which the cables are attached.
【正确答案】 B
【答案解析】[解析] 句意：一座吊桥的塔楼作为连接电缆的固定框架。framework框架，骨架。skeleton骨架。二者意思相近，可相互替换。boundary分界线。enclosure围墙。material材料。因此，本题的正确答案为B。