冷球蛋白检测时，将受检血清分装于两支试管，分别置于4℃冰箱和37℃孵箱，直立72小时

门高约（  ）米。

行政案件经过行政复议，复议机关改变原具体行政行为，行政诉讼的被告是( )

A．作出原具体行政行为的行政机关

B．复议机关

C．复议机关的上一级行政机关

D．作出原具体行政行为的行政机关和复议机关

若该病人病情反复发作且出现肺动脉瓣第二心音亢进，则提示该病人有：【 】

A．右心衰竭

B．左心衰竭

C．肺动脉高压

D．周围循环衰竭

E．主动脉压升高

脊髓亚急性联合变性的临床表现不包括（）

A.感觉性共济失调

B.痉挛性瘫痪

C.贫血

D.抑郁、易激惹等精神症状

E.节段性分离性感觉障碍

Frame Relay is simplified form of (51) , similar in principle to (52) , in which synchronous, frames of data are routed to different destinations depending on header information.

Packets are routed throught one or more Virtual Circuits known as (53) . Most Virtual Circuits are (54) , which means that the network provider sets up all DLCI connections at subscription time. (55) are also part of the Frame Relay specification. They privide a link that only lasts only as long as the session.

（52）是（）

A.X.21

B.X.25

C.X.28

D.X.29