【单选题】请根据短文的内容,回答题。 Maglev Trains (1) A few countries are using powerful electromagnets to develop high-speed trains, calledmaglev trains. Maglev is short for magnetic levitation, which means that these tra...
A.
The main components of the maglev train system
B.
High-speed maglev due to zero friction
C.
The working principle of the maglev train
D.
Differences between polarity and magnetic field
E.
Comparison of maglev trains with traditional ones
F.
Maglev with a powerful motor