如图所示，质量相等的两物体A、B叠放在粗糙的水平面上，A与B接触面光滑．A受水平

— People should spare no effort to protect the environment.

— ________.Air pollution, as is known to all, does harm to our health.[      ]

A. All right  

B. Fine

C. Go ahead  

D. Exactly

读下列两图，回答问题。

（1）甲图：亚洲和____洲的界线是____________。乙图：亚洲和_______洲的界线是____________。

（2）甲图：________运河沟通了________海和________海，连接了________洋和________洋。

（3）乙图：________海峡连通了________洋和________洋，该海峡的东面是________洲的____国。

（4）从东西半球看，甲图所示运河位于____半球；乙图所示海峡位于____半球。

为了便于供应商进行热销度分析，保证补货的及时、有效性，某超市拟在其供应商之间构建电子数据交换（EDI）系统。构成EDI系统的三个要素是EDI软硬件、通信网络和（ ）。

A．GPS技术

B．数据标准化

C．GIS技术

D．条码技术应用

我国《招标投标法》规定，依法必须进行招标的项目，其评标委员会人数应为( )人以上单数。

A．3
B．5
C．7
D．9

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