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【单选题】
设有关系R(A，B，C）和S(C，D）。与SQL语句Select A，B，D From R，S Where R．C=S．C等价的关系代数表是 A．σR．C=S．C(πA,B,D(R×S)) B．πA.
B.
D(σR．C =S．C(R×S)) C．σR．C=S．C((πA，BR)×(πDS)) D．σR．C=S．C(πD((πA，BR)×S))
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【简答题】不随时间变化的应力称为
【单选题】The computer system broke _____ suddenly while he was searching for information on the Internet. [ ]
A.
down
B.
out
C.
up
D.
in
【简答题】Können Sie mir bitte Geld ____? Ich brauche Kleingeld.
【简答题】Können Sie bitte ____zehn Minuten noch einmal anrufen?
【单选题】Automation Complacency is:
A.
overconfidence in the handling capability of the pilot.
B.
overconfidence in the handling capability of the pilot of computers.
C.
over-reliance on automation.
【单选题】Automation management need()
A.
maintenance machine well, ensure the smooth operation of the system
B.
pilots and automation to monitor each other, and keep pilots trusting the automation
C.
handover the workload to the automation system as much as possible, and give the pilot enough energy to cope with emergencies
【单选题】Chinese __________by more and more people in the world now.
A.
speak
B.
spoke
C.
is spoken
D.
was spoken
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