全面紧急停车后，外操要在第一时间将乙烯外送加热改为蒸汽加热维持其外送压力和温度稳定。
参考答案：对
关于鼻窦炎，下述说法哪项错误
A．浆液囊肿好发于上颌窦
B．黏液囊肿多位于额窦和筛窦
C．蝶窦的囊肿发生率最低
D．急性鼻窦炎有液平面、慢性鼻窦炎无液平面
E．慢性鼻窦炎，窦腔变小、密度增高
In many European countries, one has to decide much earlier what one's career is going to be, and there
is less freedom in changing one's decision _____ one has chosen a particular path. [ ]
A. once
B. before
C. until
D. as
