全国计算机等级考试四级含金量_2017年全国计算机等级考试四级模拟试题及答案7

(61) There are several periods in a computer，the shortest period is
A．Instruction period
B．Machine period
C．Beat period
D．CPU period </P><P>

　　(62) Which set is empty?
A．｛xx is a real number and x2=9 B)｛xx is a real number and x2-1=0｝
C)｛xx is a real number and x2+1=0｝ D)｛xx is a real number and x=2x+1｝ </P><P>

　　(63) What is the relation represented in the exhibit shown below?
A．R={(1,2),(1,3),(1,4),(1,5)}
B．R={(1,1),(2,2),(3,3),(4,4),(5,5)}
C．R={(1,2),(1,3),(1,4),(2,3),(4,1),(4,5),(5,5)}
D．R={(1,2),(1,3),(1,4),(2,2),(2,3),(4,1),(4,4),(4,5)} </P><P>

　　(64) What is the contrapositive of the following implication?“If it is raining，then I get wet.”
A．If I get wet，then it is raining.
B．If I am wet ，then if is raining.
C．If it is not raining, I do not get wet.
D．If I do not get wet，then it is not raining. </P><P>

　　(65) Which property does R posses? (2 grades)
Let A={1,2,3,4} and let R ={<1 2="">,<2 2="">,<3 4="">,<4 1="">}
A．Symmetry
B．Reflexivity
C．Asymmetry
D．Antisymmetry </P><P>

　　(66) When walking a tree, which traversal method yields a prefix, or Polish,form?
A．lnorder
B．Preorder
C．Postorder
D．Reorder</P><P>

　　(67) ln the following statements about graph operations, which one is NOT correct?
(2 grades)
A．Spanning tree of a graph may not be unique.
B．Minimum spanning tree of a graph may not be unique.
C．Finding critical path is an operation on directed graph.
D．Finding critical path is an operation on undirected graph. </P><P>

　　(68) Which traversal method for a binary tree does the following Pascal code illustrate? (2 grades)
procedure traverse(p:pointer);
begin
if p<>nil
then begin
traverse(p↑.left);
process(p);
traverse(p↑.right)
end
end;
A．lnorder
B．Preorder
C．Postorder
D．Reorder </P><P>

　　(69) What storage scheme does MS-DOS use for storing files on a disk?
A．I-nodes
B．a linked list allocation
C．a continuous allocation
D．a linked list with index </P><P>

　　(70) Which of the followings is NOT a condition for deadlock?
A．Starvation
B．Circular Wait
C．No Preemption
D．Mutual Exclusion </P><P>

　　(71) Assume that an operating system uses a round-robin scheduler. The process’s quantum is 20 msec,and the context switch is 5 msec. What percentage of the CPU’s time is spent on administrative overhead? (2 grades)
A．5％
B．15％
C．20％
D．25％ </P><P>

　　(72) What state is a process in when it can’t run because it needs a resource to become available? (2 grades)
A．Ready
B．Interrupt
C．Blocked
D．Running </P><P>

　　(73) The following sectors are requested from the disk:
11,1,36,16,34,9,12
What is the order of the sector reads if you are using the elevator algorithm?
(2 grades)
A．1,9,11,12,16,34,36
B．11,1,36,16,34,9,12
C．11,12,9,16,1,34,36
D．11,12,16,34,36,9,1 </P><P>

　　(74) What is the candidate key of a relational database?
A．A field with a constraint placed on it.
B．A set of fields that have no data in them.
C．A set of fields in a table used to identify a record uniquely.
D．Fields from multiple tables that are used for sorting records. </P><P>

　　(75) What Normal From is the table shown in the exhibit? (2 grades) </P><P>　　emps tbl
emp_idemp_nameemp_phonedept_namedept_phonedept_mgrname
(1) emp_id→emp_name, emp_phone, dept_name(2) dept_name→dept_phone, dept_mgrname

A．1NF
B．2NF
C．3NF
D．BCNF </P><P>
</P><P>

　　(76) Which operating system can Oracle database NOT be used in?
A．DOS
B．UNIX
C．Windows95
D．IBM Mainframes </P><P>

　　(77) Which values are NOT permitted to be part of the primary key?
A．NULL
B．punctuation
C．special characters
D．alpha-numeric characters </P><P>

　　(78) Which phase of the software engineering process results in the Software Requirements Specification?
A．definition phase
B．engineering phase
C．maintenance phase
D．development phase </P><P>

　　(79) When drawing multilevel data flow chart of top-down, the balance between parent chart and son chart must be taken into account, and to pass judgment for the balance of the charts is regularly maintained by (2 grades)
A．Output data
B．Data dictionary
C．Processing number
D．Input data </P><P>

　　(80) Which is the strictest form of cohesion?
A．logical
B．functional
C．procedural
D．coincidental </P><P>

　　(81) Which is NOT a concept of White Box Testing? (2 grades)
A．You should execute all loops at their boundary conditions.
B．You should execute all interfaces at their boundary conditions.
C．You should execute all logical decisions on their true and false sides.
D．You should execute all independent paths within a module at least once. </P><P>

　　(82) Prototyping method is a dynamic design process, it requires people who use prototyping method should have the following capability
A．Proficient program expertise
B．Immediately acquire requirement
C．Coordinate & organize eloquently
D．Handle tools smartly </P><P>

　　(83) There are two styles in the evolution of instruction set , that is CISC and RISC. Which chip belongs to the RISC?
A．i APX 432
B．VAX-11/780
C．Motorola 68000
D．Power PC </P><P>

　　(84) In advanced PC bus or local bus, which one has the fastest data throughput?
A．ISA
B．PCI
C．MCA
D．EISA </P><P>

　　(85) There are many methods in the CPETT(short for Computer Performance Evaluation Tools and Techniques). One of them is the method that runs a Kernel as the load of a computer. So we call it
A．Monitor method
B．Benchmark method
C．Model method
D．Physical method </P><P>

　　(86) There are two common types in page replacement algorithm: stack and non-stack strategies. When a real page number increase only stack algorithm can increase the hit rate monotonously. In the following replacement algorithm,which one belongs to non-stack strategy?(2 grades)
A．FIFO
B．LRU
C．PFF
D．OPT </P><P>

　　(87) What binary number is encoded with Differential Manchester in the diagram below? (2 grades)
A．10110011100
B．11001100011
C．11000110010
D．00111001101 </P><P>

　　(88) Each host or router on the Internet has its own IP address. There are four IP addresses as followings. Which IP address is erronedus?
A．189.132.2.1
B．255.255.255.0
C．198.73.265.50
D．192.0.0.3 </P><P>

　　(89) When should Frequency Division Multiplexing be used?
A．when the attenuation on a medium is greater than 25％.
B．when the white noise on the medium exceeds 50％ of the medium’s bandwidth
C．when the achievable data rate of the medium exceeds the data rate of the digital signals to be transmitted
D．when the useful bandwidth of the medium exceeds the required bandwidth of the digital signals to be transmited </P><P>

　　(90) The universe of hypertext servers that allow text, graphics, sound, and other multimedia files to be viewed togather and navigated via hypertext links. It is now the fastest growing area of the Internet. It is
A．Gopher
B．WWW
C．E-mail
D．FTP

</P><P>
61.B 62.C 63.D 64.D * 65.D 　
66.B * 67.C * 68.A 69.C 70.A 　
* 71.C 72.C * 73.D 74.C * 75.B 　
76.A 77.A 78.A * 79.B 80.B 　
* 81.B 82.B 83.D 84.B 85.B 　
* 86.A * 87.B 88.C 89.D 90.B 　

2017年全国计算机等级考试四级模拟试题及答案7.doc

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