【判断题】经纬观测水平角时上半测回采用盘右顺时针观测,下半测回采用盘左逆时针观测。
【简答题】I have a good friend. (1) Chinese name is Da Shan and his (2) name is Mark Roswell. He (3) from Canada. He can (4) English and French (法语). And he speaks Chinese very (5 ) . He likes China very much. ...
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【单选题】1N4007二极管反向耐压峰值为多少伏?