题型:单项选择题 You can't help but hear commercials; every few minutes the program is interrupted to give you one advertising ______.A.so on and so forthB.more or lessC.something or otherD.sooner or later 查看答案
题型:选择题 某溶液中含有大量Fe2+、Fe3+、Mg2+和NH4+,其C(H+)= 10-2mol/L,在该溶液中可以大量存在的阴离子是( )A.SO42-B.NO3-C.SCN-D.CO32- 查看答案