下列试剂中,一次就能鉴别出MgSO4、NH4Cl、KNO3三种溶液的是[ ]
A.AgNO3溶液
B.BaCl2溶液
C.NaOH溶液
D.CuCl2溶液
答案:C
中国长篇章回小说是怎样形成的?
__________ you understand the rule, you will have no further difficulty.
A.While
B.Once
C.Though
D.Unless