当三相电源对称时，异步电动机在额定电压下的（）空载电流，任何一相与（）的偏差不得大于平均值的10％。
参考答案：三相；平均值
阅读短文，用合适的单词填空。
Mr. Green is from England. He teaches English in a middle school. He speaks some Chinese, but only
a little. He goes to Chinese classes every week. He likes working in China very much. He says the
Chinese people are very kind to him. He has a son and a daughter. They go to school here, too. But
they go to a different school.
Mr. Green is ____ (1). He is a ____ (2) of English. He can speak some ____ (3), but ____ (4)
____ (5). He goes to Chinese classes every week. He likes working in China. He says the Chinese
people are very _____ (6). He has ____(7) ____(8). They go to school here. They ____ (9) in
different ____ (10).
治疗哮喘最有效的抗炎药是( )
A．茶碱类B．肾上腺受体激动剂C．抗胆碱药物D．糖皮质激素E．白三烯拈抗剂
