问题详情

Several countries in the world are using strong electromagnets __________. 查看材料
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请帮忙给出正确答案和分析，谢谢！