压入式局部通风机和启动装置安设的位置距回风口不得小于()米。
A.5
B.10
C.15
D.20
参考答案:B
某血管活性物质的作用是刺激支气管平滑肌强烈持久性的收缩,也使毛细血管通透性增强和促进内分泌作用,该物质是()
A.血小板活化因子
B.组胺
C.白三烯
D.前列腺素
E.激肽
I would have paid _____ for the dress if the sales girl had insisted, because I really wanted it. [ ]
A. as much twice
B. twice as much
C. twice more than
D. more than twice