We’ve  made it a rule that ___________ comes home first cooks supper for the whole family.

A．whichever

B．whatever

C．who

D．whoever

溶液析出晶体后，其剩余溶液是 [ ]

A．饱和溶液

B．不饱和溶液

C．只有溶剂

D．稀溶液