Amy has no idea_________her summer holidays.

A．what she should spend

B．when should she spend

C．where she should spend

D．how should she spend

旁路系统投入原则为：先投（）旁路，后投（）旁路；投低压旁路时，应先投（）后投（）；投高压旁路时，应先投（）后投（）。在一般的操作情况下，减温水应投（）控制。