听力原文: Although I think the United States generally has an excellent system of transpor
High speed trains may be an answer. One fairly new proposal for such trains is for some- thing called a Maglev, meaning a magnetically levitated train. Maglev will not actually ride on the tracks, but will fly above tracks that are magnetically activated. This will save wear and tear on the tracks. These trains will be able to go faster than 150 miles per hour. At this speed, conventional trains have trouble staying on the tracks.
As you can see, Maglev offers exciting possibilities for the future.
What is the main topic of the talk?
A.Energy conversation.
B.Transportation of the future.
C.Transportation problem.
D.Advantages of air transportation over railroad.