枣核式绳帽由绳帽体、枣核式绳芯、（）和压帽等组成。
A、钢球
B、铁球
C、木质球
D、软质球
参考答案：A
On hearing a phone call from his wife ____ she had a fall, Mr. Gordon immediately rushed
home from his office. [ ]
A. says
B. said
C. saying
D. to say
避雷针的引下线常用直径（）mm的圆钢制成。
A、不大于6
B、不大于4
C、不小于4
D、不小于6
