Eithertheshirtsorthesweater()agoodbuy
A. is
B. has
C. are
D. was
Everysocietyhasitsownpeculiarcustomsand()ofacting.
A. attitudes
B. behavior
C. ways
D. means
在有源逆变电路中,逆变角的移相范围应选()为最好。
A. =90º∽180º
B. =35º∽90º
C. =0º∽90º
除了标准RCCM和ASME中规定的阀体气压试验,应根据EN1266-1和EN1266-2执行以下附加试验()。
A. 阀体密闭性(P11)
B. 阀坐密闭性(P12)
C. 阀塞或阀瓣强度(P20)
D. 背座密封性(P21)
E. 阀门的操作(F20)