填空题 A to develop a maglev train rail system
B To explain why maglev trains are faster
C to pull and push the train forward
D to create a magnetic field
E to experiment with the maglev train
F to travel from Paris to Rome in about two hours

填空题 Several countries in the world are using strong electromagnets ______.

填空题 You can connect a wire to the positive and negative ends of a battery ______.

填空题 A unique system of magnetic fields is created by the coils ______.

填空题 The frictionless maglev train enables you ______.