A:HCO3-、Al3+、Na+、SO42-
B:I-、NO3-、K+、NH4+
C:MnO4-、Cl-、SO42-、K+
D:SiO32-、SO32-、Na+、Cl-
如果把分式 中的x和y都扩大10倍,则分式的值( ).
The fire spread through the hotel very quickly but everyone get out.