your shared Ethernet of token-ring LAN is tough call. Users and analysts involved in(101)high-speed LANs have learned the benefits of each. However, there are trade-offs to each, and(102)which fast LAN technology to choose is critical for(103)network performance problems and(104)costly purchasing mistakes.

A．a(chǎn)voiding

B．clipping

C．choosing

D．deciding

E．dissolving

A．impossible

B．fearful

C．feasible

D．program

E．question

vides a(126)for information exchange among those devices. The scope of the LAN is small typically a single building or a cluster(叢)of buildings. The LAN is usually owned by the same organization that owns the(127)devices. The internal data rate of LAN is at least several Mb/s.The basic of LAN communication is broadcasting. At each station, there is a transmitter/receiver that communicates over a(128)shared, By other stations. A transmission from any one station is(129)to and received by all other stations.

A．broadcast

B．cable

C．control

D．interconnects

E．internet

A．look

B．looks

C．a(chǎn)ccount

D．a(chǎn)ccounts

esponse-oriented systems.The goal of(150)-oriented multiprocessing is to obtain high(150)(151)minimal computing cost. The techniques employed by multiprocessor operating systems to achieve this goal take advantage of an inherent processing versus input/output balance in the workload to produce(152)and(153). loading of system(154)

A．though

B．through

C．throughout

D．throughput

關(guān)系數(shù)據(jù)庫中有三種基本操作，從表中選出滿足某種條件的元素的操作稱為( )。

A．選擇

B．投影

C．連接

D．掃描

由計算機、操作系統(tǒng)、DBMS、數(shù)據(jù)庫、應(yīng)用程序及用戶等組成的一個整體叫( )。

A．?dāng)?shù)據(jù)庫系統(tǒng)

B．?dāng)?shù)據(jù)庫管理系統(tǒng)

C．文件系統(tǒng)

D．軟件系統(tǒng)

數(shù)據(jù)管理技術(shù)經(jīng)歷的人工管理階段的特點是( )。

A．?dāng)?shù)據(jù)和程序是相互獨立的

B．?dāng)?shù)據(jù)和程序緊密地結(jié)合

C．由程序產(chǎn)生數(shù)據(jù)

D．程序員編制程序時可以不考慮數(shù)據(jù)的存儲結(jié)構(gòu)

數(shù)據(jù)管理技術(shù)經(jīng)歷的數(shù)據(jù)庫管理階段的特點是( )。

A．?dāng)?shù)據(jù)和程序緊密地結(jié)合

B．由程序產(chǎn)生數(shù)據(jù)

C．程序和數(shù)據(jù)一一對應(yīng)

D．實現(xiàn)了數(shù)據(jù)共享、數(shù)據(jù)獨立性及完整性等

設(shè)關(guān)系模式R(A，B，C，D)，F(xiàn)是R上成立的FD集，F(xiàn)={AB→C，D→B}，ρ={ACD，BD}是R上的一個分解，那么分解ρ______。

A．保持函數(shù)依賴集F

B．丟失了AB→C

C．丟失了D→B

D．是否保持FD，由R的當(dāng)前關(guān)系確定