【单选题】How does the great power system of the twentieth century compare with that of the eighteenth and nineteenth centuries?
A.
The great power system in the twentieth century was global, whereas the great power system in the eighteenth and nineteenth centuries was European.
B.
The United States dominated the great power system of the twentieth century, whereas France dominated the great power system of the eighteenth and nineteenth centuries.
C.
The Concert of Europe was a feature of the great power system of the twentieth century, whereas the great power system of the eighteenth and nineteenth centuries saw constant conflict in Europe.
D.
World Wars I and II were major conflicts in the great power system of the twentieth century, whereas the great power system of the eighteenth and nineteenth centuries saw no major conflicts as Britain served as an effective balancer.
【单选题】The electrical power system makes, supplies, and controls electrical power to the airplane. The system has these subsystems: external power; generator drive system; AC generation; AC electrical load d...
A.
external power can supply elctricity to airplane in flight
B.
the generator daive the engine on the airplane through "generator drive system"
C.
"AC generation" means the people borned in the age of AC time
D.
AC electrical laod distribution system is used to distribute the electriciy to the electric loads