某试样包含四个组分，它们在色谱柱上的分配系数分别为：K1=21，K2=30，K3=59，K4=87。则最先流出色谱柱的组分是()
A. 1＃组分
B. 2＃组分
C. 3＃组分
D. 4＃组分
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磷以MgNH4PO4·6H2O形式沉淀，经过滤，洗涤后用适量HCl标准溶液溶解，而后以NaOH标准溶液返滴定，选甲基橙为指示剂，此时磷与HCl的物质的量之比是()。
A. 1：3
B. 3：1
C. 1：2
D. 1：1
The author indicates in the passage that conflict______.
A. is an inevitable struggle resulting from competition
B. reflects the struggle among social entities
C. is an opposition among individual social animals
D. can be avoided
In the author's opinion, the speaker______.
A. gave a correct judgement of the English level of students
B. had exaggerated the language problems of the students
C. was right in saying that English teachers were not doing their jobs
D. could think and speak intelligently
Which of the following is the best title for the passage？
A. The Life Cycle of Locusts.
B. Migratory Locusts in the United States.
C. Locust Plagues in Nebraska.
D. The Reproductive Capability of the Locust.
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