A certificated lifeboatman assigned to command the lifeboat should（）.

A.be the first individual to board the craft

B.drain the hydraulic pressure before lowering the craft

C.have a list of the persons assigned to the lifeboat

D.All of the above

唯物主义与唯心主义的对立，在于是否承认

A．世界的运动变化

B．世界的存在性

C．世界的物质性

D．意识的能动性