望远镜对光的步骤是()。
A.物镜对光、目镜对光、消除视差
B.目镜对光、物镜对光、消除视差
C.目镜对光、消除视差、物镜对光
D.物镜对光、消除视差、目镜对光
参考答案:B
Email,as well as telephones ________ an important part in daily communication.[ ]
A. is playing
B. have played
C. are playing
D. play
领导手段