【简答题】Listen to a conversation and choose the best answer to each question you hear. 1 A. He is not happy with his pay. B. He loses interest in his job. C. He is afraid of losing his job. D. He wants to ch...
【单选题】--- She looks very happy. She ______ have passed the exam. --- I guess so. It’s not difficult after all. A. should B. could C. must D. might
【简答题】新视野U-4 U1_1_1d.wmv 1. The most difficult thing 1) is Mandarin Chinese. I did it in evening classes a few years ago and I 2) it really, really difficult. 2. Probably capoeira, which is a Brazilian danc...
【单选题】按《重庆市建设工程费用定额》(2008)规定,按实计算费用包括()。
【简答题】新视野U-4 U1_1_1d.wmv 1. The most difficult thing 1) is Mandarin Chinese. I did it in evening classes a few years ago and I 2) it really, really difficult. 2. Probably capoeira, which is a Brazilian danc...
【单选题】关于绕线型异步电动机转子串频敏变阻器起动方式的特点,下列叙述错误的是( )。
A.
频敏变阻器相当于一个铁心损耗很大的三相电抗器
B.
在起动过程中,频敏变阻器的电抗值和对应于铁心涡流损耗的等效电阻值随着转子电流频率的减小而自动增加
C.
随着电动机转速的增高,频敏变阻器自动平滑地减小阻抗值,从而可以限制起动电流
D.
频敏变阻器不需经过分级切换电阻就可以使电动机平稳起动