以下程序不可能出现的的输出结果为（ ）。a=int(input())try: if a>0:print(a) else: raise ValueError(a)except ValueError as e: print("Error:",e)finally:print("end")
A. -5Error: -5end
B. 55end
C. 0Error: 0end
D. -100-100end
以下程序的输出结果为（ ）。a=[i for i in range(6)]try: for t in a:if t%4==3: raise else: print(t,end=" ")except: print("end")
A. 0 1 2
B. 0 1 2 end
C. 0 1 2 3 end
D. 0 1 2 3 4
Which of the following tasks are before-flight duties?
A. I may take part inpre-flight briefings.
B. I mustdemonstrate how to use emergency equipment.
C. I must performpre-flight checks.
D. I need to greetpassengers as they board.
E. I need to direct passengers to their seats.
F. I may sellduty-free items.
Which of the following tasks are on-flight duties?
A. I need to greetpassengers as they board.
B. I must demonstratehow to use emergency equipment.
C. I must ensurethat hand-luggage is securely stowed.
D. I may makeannouncements.
E. I need to servefood and drink.
F. I may sellduty-free items.
G. Ineed to completeflight reports after the journey.
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