循环机密封油建立具备的条件是（）。
A、润滑油系统运行正常
B、密封气投用
C、压缩机缸体导淋打开
D、透平暖机合格
参考答案：A, B
2-糠醛
Which of the following statements is the most appropriate title for the passage a. The Origins of GPS b. The Advantages of GPS c. The Future of GPS d. The Increasing Uses of GPS: Military and Civilian
