单选题
According to the passage, when could people start using a maglev commerciaily?
A、
In 5 years.
B、
In 10 years.
C、
In 20 years.
D、
In more than 20 years.
【正确答案】
B
【答案解析】
[注释] 根据第一个句子“The next decade could see…”，可以确认答案。
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