_____ you free tomorrow afternoon? [ ]
A. Do
B. Am
C. Is
D. Are
答案:D
つうかん
A.通感
B. 通観
C.痛観
D.痛感
严禁井下配电变压器中性点直接接地;严禁由地面中性点直接接地的变压器或发电机直接向井下供电()