What did Vic do whe they met one day the auther was going down the steps of the school library ?
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How did the author know the boy’s name?
How did the author feel when the boy glanced at her?
Did they get married or not?
船用雷达是建立在无线电波在任何两种媒质的边界面上必然产生反射,以及____等基本传播特性的基础上的。
A. 无线电波的传播是沿地表进行的
B. 无线电波的传播是沿直线进行的
C. 无线电波的传播速度是常数
D. 无线电波的传播是沿直线进行的,且传播速度是常数
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