Inmarsat-F站的识别码是()。
A、704120123
B、664121234
C、674121234
D、764120123
参考答案:D
President Hu' s visit to Australia, ___ first by a Chinese president in 12 years, is considered of ___ great importance to global economic situation at present.[ ]
A. a; \
B. the ; a
C. the; the
D. the; \
控制图中有三条线,中间一条线为中心线,上、下两条线分别为上、下控制线,这两条线距中心线的距离等于()。
A.6σ
B.4σ
C.3σ
D.2σ