单项选择题
A.克,g B.毫克,mg C.千克(公斤),kg D.克,G
A.2.7,57.6 B.2.7,57.7 C.2.8,57.6 D.2.8,57.7
A.-0.014 B.+0.014 C.+0.011 D.+0.003