小磁针的指向如图所示,请画出螺线管的极性和电流方向。
A low-carbon lifestyle has ______ effect on our daily life. People are paying more and more attention to saving ______ these days.[ ]
A. the, energies
B. a, energy
C. an, energy
D. a, energies
电子商务网站建设一般经过的主要步骤有()
A.域名注册
B.建立主机并确定主机位置
C.硬件选择
D.软件选择