A)Hisflighthasbeencancelled. B)Hehastomeethislawyer. C)Hewasinjuredinanaccident. D)Heissufferingfromafever.
A)Holdingatelephonemeetinginstead. B)HavingitatthesametimenextMonday. C) Askingtheir assistants to attend it. D)Puttingitoffuntilnextmonth.
A. 输出电压与转速成正比 B. 输出电压与转角成正比 C. 转速与脉冲量成正比 D. 转速与脉冲频率成正比
A. 对 B. 错
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