以静脉注射剂为参比制剂所得的生物利用度 A．肠肝循环 B．肝脏首过效应 C．生物等效

若等腰三角形一腰上的高等于腰长的一半，则该三角形的底角为（     ）。

（）是客家聚族而居以维持家族共居的基本条件。

A.向心性

B.中轴性

C.祠宅合一

D.围合性

下列哪一项不是超声诊断异位妊娠声像图的表现:

A.子宫增大 

B.子宫直肠陷凹积液 

C.附件区囊实性包块 

D.宫腔积液 

E.子宫内膜呈细线状 

物体受到的力一般可以分为两类；一类是使物体运动或使物体有运动趋势，称为（）。

A、重力

B、压力

C、被动力

D、主动力

Both bus and tree topologies are characterized by the use of multipoint (71) ．For the bus，all stations attach，through appropriate hardware (72) 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 from the (73) ．A transmission from any station propagates the length of the medium in both directions and can be received by all other (74) ．At each end of the bus is a (75) ，which absorbs any signal，removing it from the bus．

A．tap
B．repeater
C．terminator
D．concentrator