A:滤渣中一定有Zn
B:滤渣中一定有Ag和Cu
C:滤渣中可能有Cu
D:滤液中一定有Ag+和Cu2+
“坐地日行八万里,巡天遥看一千河”描述的是地球的( )
As is often the case, little Tom, if ____________, is most likely to stop crying soon.