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问题 选择题
若分式
1
1-2x
有意义，则x的取值范围是（　　）
A．x＞
1
2
B．x≠
1
2
C．x＞-
1
2
D．x＜
1
2
答案

当分母1-2x≠0，即x≠

1
2
时，分式
1
1-2x
有意义．

故选B．

单项选择题 A1/A2型题

患者，26岁，行右侧腮腺混合瘤摘除术，局麻后立即出现面色苍白、紫绀、神智丧失、呼吸困难、恶心、呕吐、烦躁不安、面肌抽搐、血压下降，其原因应首先考虑（）

A.晕厥

B.肾上腺素反应

C.普鲁卡因过敏

D.普鲁卡因中毒

E.癔病
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单项选择题

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.

（51）是（）

A. Datagram Switching

B. Datagram Routing

C. Packet Switching

D. packet Routing
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