韶山3型电力机车升弓压缩机的气压为()。
A.700~900kPa
B.300~500kPa
C.900kPa
D.300kPa
参考答案:C
The ______ in the mountain village struck most of the visitors.
A.scenes
B.space
C.absence
D.flight
分析P、I、D调节规律的各自特点。