给试管中的液体物质加热时，错误的操作是（　　）

A．加热时要先进行预热

B．用酒精灯的内焰加热

C．试管与桌面成45°角

D．液体体积不超过试管容积的

Which of the following is reasonable in explaining the integration

A．Integration is making choices about where to concentrate resource So sacrifice is inevitabl

B．Since the project managements are implemented by overlapping and iteratively, integration is neccessar

C．“Trade-off” means “give and take”. It is necessary in dealing with various stakeholder

D．The project deliverables are not integrated with ongoing operations of the customer's organizatio