单管塔依据其连接技术不同又分为（）单管塔和插接连接单管塔。
A.法兰连接
B.垂直连接
C.水平连接
D.交叉连接
参考答案：A
吗啡中毒的特异性拮抗药是( )。
A．肾上腺素B．纳洛酮C．阿托品D．解磷定E．氯化钙
We might need more food,_ how many people turn up. [ ]
A. depending on
B. going on
C. having on
D. looking on
