为十八反配伍的是（） A.甘遂与牵牛子 B.巴豆与牵牛子 C.乌头与贝母

----- _______ school were you at last year?

----- Centre School.

A．What

B．Which

C．That

D．Where

根据《民法通则》的规定，被代理人出具的授权委托书授权不明的，应当由( )。

A．被代理人对第三人承担民事责任，代理人不负责任
B．被代理人对第三人承担民事责任，代理人员连带责任
C．代理人对第三人承担民事责任，被代理人不负责任
D．先由代理人对第三人承担民事责任，代理人无法承担责任的，由被代理人承担责任

对于样本数据：1，2，3，2，2，以下判断：①平均数为5；②中位数为2；③众数为2；④极差为2．正确的有（　　）

A．1个

B．2个

C．3个

D．4个

数据仓库的体系结构中，中间层为______服务器。

Both bus and tree topologies are characterized by the use of multipoint (1).For the bus, all stations attach, through appropriate hardware (2) 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(3). A transmission from any station propagates the length of the medium in both directions and can be received by all other  (4). At each end of the bus is a (5) , which absorbs any signal, removing it from the bus.

空白（5）处应选择（）

A.tap

B.repeat

C.terminator

D.concentrator