Ⅱ型梁桥一般只用于( )的小跨径桥梁。
A．6～12m B．7.5～20mC．20～40m D．16～20m
参考答案：A
Low temperatures and freezing rain in some parts of China also pushed up ________ of agricultural
products during the early weeks of 2011. [ ]
A. benefits
B. interests
C. prices
D. welfares
对心肌可产生直接抑制作用的麻醉镇痛药是（）
A.吗啡
B.芬太尼
C.舒芬太尼
D.哌替啶
E.阿芬太尼
