【单选题】The Boeing Company has completed the Power On sequence for the first 787 Dreamliner, marking the completion of the next major milestone on the path to first flight later this year. Power On means:
A.
to put swich on
B.
a complex series of tasks and tests that bring electrical power onto the airplane and begin to exercise the use of the electrical systems
【简答题】On the premise of ensuring the completion of transport tasks, what issues should be considered in determining all possible major technical standard schemes for railway lines?