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举一反三
【单选题】The biggest safety threat facing airlines today may not be a terrorist with a gun, but the man with the portable computer in business class. In the last 15 years, pilots have reported well over 100 in...
A.
is in favor of prohibiting passengers’ use of electronic devices completely
B.
has overestimated the danger of electromagnetic interference
C.
hasn’t formed his own opinion on this problem
D.
regards it as unreasonable to exercise a total ban during flight
【单选题】装PRV等部件的通用原则是（）
A.
先连接好管路、电插头、接地线等外围件，再固定PRV本体，最后拧紧各管路、插头等
B.
先拧紧好管路、电插头、接地线等外围件，再装PRV本体
C.
先固定PRV本体，再连接好管路、电插头、接地线等外围件，最后拧紧各管路、插头等
D.
没有先后次序