汽轮机采用变压运行汽压降低，汽温不变时，汽轮机各级容积流量，流速近似（），能在低负荷时保持汽轮机内效率（）。
参考答案：不变、不下降
—__________?
—No, it’s on the sofa.
A．Where is your sweater
B．Is this an English book
C．What color is your bag
D．Is your pen in the pencil box
---I feel really tired.
---___________________ [ ]
A. Lucky you!
B. You’d better work harder.
C. Congratulation!
D. Why not go and have a reat?
