I'm not a student, he isn't _______. [ ]
A. too
B. either
C. also
D. as well
答案:B
由四舍五人法得到的近似数0.690有( )个有效数字,分别是( ),它精确到( )位。
线路、电缆工作票进入变电站时如何办理工作票?