氧枪喷头的主要参数有（）、（）、（）、（）、入口直径和多喷头的小孔与喷头中心线的夹角等。
参考答案：喉口直径；出口直径；扩张段长度；扩张段角度。
造价员资格证书原则上每（）年检验一次。
A．3
B．4
C．2
D．1
Their new bridge is being built now, which is said to be ______the old one.[ ]
A. the length three times of
B. three times the length of
C. three times as longer as
D. three times the length as
