启动往复式压缩机时,应先()。
A.开启进气阀
B.关闭进气阀
C.进气阀开启一半
D.不作要求
参考答案:B
I enjoy my new life here. But I still miss my old friends from time to time. Here the underlined part means .
A.sometimes
B.at all times
C.always
D.Usually
经产前检查,医师发现或者怀疑胎儿异常的,应当对妊娠妇女进行()
A.产前诊断
B.母婴保健
C.妊娠妇女保健
D.胎儿保健
E.产妇保健