用薄层色谱法对待测组分定性时,主要依据
A. 比移值Rf
B. 斑点的大小
C. 斑点的颜色
D. 斑点至原点的距离
Which type do the six letters belong to?
A. Formal letter
B. Informal letter
Gather information of the writers of the letters and their daughter.(填写对应序号)1.Father's name:2.Father's occupation:3.Father's location:4.Mother's name:5.Mother's occupation:6.Mother's location:7.Time for father and mother to writer and read the letters:8.Daughter's name:9.Daughter's occupation:10.Daughter's location:11.Time for daughter to writer and read the letters: