A:《南京条约》
B:《北京条约》
C:《马关条约》
D:《辛丑条约》
— There ___________ a picture on the wall for a long time.
— Oh, right. It's so beautiful.
只用一种试剂就能鉴别Ba(NO3)2、NaCl、KOH三种无色溶液,可选用的试剂是( )