()年国际人机工程协会(IEA)成立。
参考答案:1960
— Why do you always go to Lanzhou University on weekends?
— Because there’re lots of great speakers I can practice English ________ in the English Corner there.
A. with
B.to
C.on
D.about
执行器电机送电前,用500V兆欧表进行绝缘检查,绝缘电阻应不小于()。