Both bus and tree topologies are characterized by the use of multipoint （） . For the bus, all stations attach, through appropriate hardware （） known as a tap, directly to a linear transmission medium, or bus. Full-duplex operation between the station and the tap allows data to be transmitted onto the bus and received fromthe （） . A transmission from any station propagates the length of the medium in both directions and can be received by all other （） . At each end of the bus is a （） , which absorbs any signal, removing it from the bus.

Both bus and tree topologies are characterized by the use of multipoint（）.

A．medium

B．connection

C．token

D．resource

“总加工流程优化”是影响企业用能过程的重要影响因素，尤其对新设计炼厂，总加工流程对能耗构成和用能方案的影响更加突出。表现在（）。

A.影响炼油过程的燃料产、用状况

B.影响热量的匹配平衡关系

C.影响蒸汽及动力的产、用平衡关系

D.影响产品质量