(68) Which of the following statements is true regarding simple sort techniques? (2 Points)
　　A．Exchange sort is frequently referred to as a bubble sort.
　　B．Exchange sort is the least expensive.
　　C．If random data are in an array that is to be sorted，an Insertion Sort will give the best performance for large elements with small sort items.
　　D．Both Insertion Sort and Selection Sort require O(n)moves.

　　(69) Which UNIX command creates a symbolic link named myfile in the current directory to the file/etc/hosts?
　　A．In -s /etc/hosts myfile
　　B．In -s myfile /etc/hosts
　　C．link -s /etc/hosts myfile
　　D．link -s myfile /etc/hosts

　　(70) Which MS-DOS command is correct?
　　A．DEL /s *.bat
　　B．DEL *.exe/sp
　　C．DEL *.obj >nul:
　　D．DEL *.com *.sys

      (71) A virtual memory system has five virtual pages numbered zero through four and three page frames. All the page frames are initially empty. How many page faults are generated with the following access sequence using a FIFO replacement policy? (2 Points)
　　0 1 2 3 0 1 4 0 1 2 3 4
　　A．8
　　B．9
　　C．10
　　D．11

　　(72) Which element is NOT part of a microkernel? (2 Points)
　　A．basic I/O
　　B．a file system
　　C．IPC mechanisms
　　D．memory management

　　(73) Which is local to a thread instead of a process? (2 Points)
　　A．a stack
　　B．an open file
　　C．a semaphores
　　D．an address space

　　(74) What is a subselect statement?
　　A．a select statement that selects a subset of fields in a table
　　B．a select statement that returns a subset of the data in a table
　　C．a select statement that appears within another select statement
　　D．a select statement that returns a subset of the constraints on a field

　　(75) In developing a hospital database，it is determined that on the average，each patient will have 6 treatments during a hospital stay. The averge length of a stay is three days.The hospital has 1000 beds. There are on the average 800 patients occupying beds each day. The relationship between PATIENT and TREATMENT is l: M. The relationship between PATIENT and BED is 1: 1， conditional. If treatment record occurrences are archived as soon as a patient is discharded from the hospital，how many occurrences of the TREATMENT records will be stored in the TREATMENT database file on the average? (2 Points)
　　A．6,000
　　B．4,800
　　C．18,000 D)1,600

　　(76) Which of the following conditions will make a relation that is in first normal form to be in second normal form?
　　Ⅰ.every non-key attribute is functionally dependent on the full set of primary key attributes.
　　Ⅱ.no non-key attributes exist in the relation.
　　Ⅲ.the primary key consists of only one attribute.
　　A．Ⅰ only
　　B．Ⅰand Ⅱ only
　　C．Ⅰand Ⅲ only
　　D．any of them

　　(77) The most commonly used locking level in implementing concurrency control is at which of the following levels?
　　A．database
　　B．table