A.4
B.5
C.6
D.9
E.10
第1题:
设关系R与关系S具有相同的目,且相对应的属性的值取自同一个域,则R ∩ S可记作
A.{t | t ∈R ∨ t ∈S}
B.{t | t ∈R ∧ tS}
C.{t | t ∈ R ∧ t ∈ S}
D.{t | t ∈ R ∨ tS}
第2题:
A flesh ;
B fresh ;
C flash
第3题:
设关系R和关系S的元素分别是4和5,关系T是R与S的笛卡尔积,即:T= R×S,则关系T的元数是( )。
A.9
B.16
C.20
D.25
第4题:
设关系R、s和T分别如下图所示,其中T是R和S的一种操作结果。则
A.T=R ∞S
B.T=R∞SC<E R.B=S.B
C.T=R ∞s
D.T=R×S
第5题:
设关系R和S的元数分别是r和s,则集合{t|t=<tr,ts>∧tr ∈R∧ts∈S}标记的是
A.R∪S
B.R-S
C.R∩S
D.R×S
第6题:
( 35 )设关系 R, S 和 T 分别如下图所示,其中 T 是 R 和 S 的一种操作结果。则
第7题:
设关系R和关系S的元数分别是5和4,关系T是R和S的广义笛卡尔积,即:T=R×S,则关系T的元数是( )。
A.7
B.9
C.12
D.16
第8题:
● 设关系R是4元关系,关系S是一个5元关系,关系T是R与S的笛卡尔积,即T=R×S,则关系T是 () 元关系。()A.9 B.11 C.20 D.40
第9题:
第10题:
a worker's achievements
a worker's potential for a certain job
a worker's psychological problem
a worker's motivation for a certain job
第11题:
the steps in which work is done
the state of mind of a worker when working
the effect of working environment on a worker
the value of the product a worker is making
第12题:
2
3
4
5
第13题:
Henry's job was to examine cars which crossed the frontier to make sure that they were not smuggling anything into the country. Every morning,except at weekends,he (11) see a factory worker coming up the hill towards the frontier, (12) a bicycle with a big load of old straw on it. When the bicycle arrived the frontier,Henry used to stop the man and order him to take the straw off. Then he would examine the straw very carefully to see (13) he could find anything,after which he would look in all the man's pockets before he let him tie the straw up again. The man would then put it on his bicycle and go off down the hill with it. Although Henry was always (14) to find gold or jewelry or other valuable things hidden in the straw,he never found (15) ,even though he examined it very carefully. He was sure that the man was smuggling something,but he was not (16) 鱼to imagine what it could be.
Then one evening,after he had looked through the straw and emptied the factory worker's pockets (17) usual,he said to him,“Listen,I know that you are smuggling things (18) this frontier. Won't you tell me what it is that you're bringing into the country so successfully? I'm an old man,and today's my last day on the job. Tomorrow I'm going to (19) . I promise that I shall not tell anyone if you tell me what you've been smuggling. ”The factory worker did not say anything for (20) . Then he smiled,turned to Henry and said quietly:“Bicycles. ”
A. should
B. might
C. would
D. must
第14题:
He doesn’t believe the worker can ____________ to assemble the motorcycle all by himself.
A、succeed
B、pursue
C、manage
D、handle
第15题:
A.4
B.5
C.6
D.9
E.10
第16题:
设关系R与关系S具有相同的目,且相对应的属性的值取自同一个域,则R∪S可记作
A.{t | t∈R∨t∈S}
B.
C.{t | t∈R∧t∈S}
D.
第17题:
设关系R是4元关系,关系S是一个5元关系,关系T是R与S的笛卡儿积,即T=R×S,则关系T是______元关系
A.9
B.11
C.20
D.40
第18题:
设关系R与关系S具有相同的目,且相对应的属性的值取自同一个域,则R∩S可记作________。
A.{t|t∈R∨t∈S}
B.{t|t∈R∧t┐∈S}("┐∈"表示"不属于")
C.{t|t∈R∧t∈S}
D.{t|t∈R∨t┐∈S)("┐∈"表示"不属于")
第19题:
函数strcmp( )的功能是对两个字符串进行比较,当s所指字符串和t所指字符串相等时,返回值为0;
当s所指字符串大于t所指字符串时,返回值大于0;当s所指字符串小于t所指字符串时,返回值小于
0(功能等同于库函数strcmp( ) ),请填空。
include <stdio.h>
int strcmp ( chat * s, char * t)
{ while( * s && * t && * s=【 】
{ s++;t++; }
return 【 】;
}
第20题:
A
In a small village, there is a teacher, a nurse(护士) ,a driver(司机) and a worker.They are good friends. What are their names? One is Mike, one is Jack, one is Tom and the other is John. Mike's, Jack’s and Tom-s children are classmates. John doesn’t have any children He teaches his friends' children at school. Mike has many hens. He gives the driver and the nurse eggs. Jack's child goes to the nurse- s house. The nurse-s house is beside Jack's.
( )21. Are the four people good friends?
A. Yes.
B. No.
C. Not.
D. They are brothers.
第21题:
若INDEX(S,T)表示求T在S中的位置的操作,则对于S=“Beijing&Nanjing”,T=“jing”,INDEX(S,T)=()
第22题:
第23题:
R∪S
R-S
R∩S
R×S