桥梁下部组成内容包括( )。
A．桥墩、桥台、地基基础
B．桥墩、桥台、基础、排水系统
C．桥墩、桥台、排水系统
D．桥墩、桥台
参考答案：D
It's less expensive to buy goods in ___, but you'd better examine the ___ before buying them. [ ]
A. quantity ; quality
B. quantity ; quantity
C. quality ; quality
D. quality ; quantity
覆环（围带）断裂时应如何处理？
