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【简答题】
当空气中被测组分浓度较所用的检测方法灵敏度很,一般选用直接采样法来采集气态样品,常用的采样器有( ) 、 ( ) 、( )和( ) 。
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举一反三
【单选题】听力原文：M: Didn't you say you would go to the convention this morning? W: Yes, but it was postponed until next Wednesday. Q: What does the woman mean? (19)
A.
The convention was cancelled.
B.
The convention was put off.
C.
The convention was held last Wednesday.
D.
The convention was overcrowded.
【简答题】Le chemin ( ) je suis passé est plus court.