脱乙烷塔进料后氮气赶尽以后压力还是偏高，可能的原因是（）。
A、原料中碳二含量偏高
B、塔底热源过大
C、塔底抽出太小
D、塔顶回流偏小
参考答案：A, B
—Mother, I climbed up to that tall tree and picked this big apple.
—Jesus! You______ down and hurt yourself.
A．might have fallen
B．might fall
C．must have fallen
D．must fall
试述呕吐痰饮内阻证的症状、治法与代表方剂
