已知3个表: Student表结构列名含义数据类型约束Sno学号普通编码定字串,长

题型:问答题

问题:

已知3个表:

Student表结构
列名含义数据类型约束
Sno学号普通编码定字串,长度为7主码
Sname姓名普通编码定长字符串,长度为10非空
Ssex性别普通编码定长字符串,长度为2取值范围为:{男女,}
Sage年龄微整型大于等于14
Sdept所在系普通编码不定长字符串,长度为20
Course表结构
列名含义数据类型约束
Cno课程号普通编码定字串,长度为10主码
Cname课程名普通编码定长字符串,长度为20非空
Periods学时数小整型大于0
Porperty课程性质普通编码定长字符串,长度为4取值范围为:{必修,选修}
SC表结构
列名含义数据类型约束
Sno学号普通编码定字串,长度为7主码,引用Student的名码
Cno课程号普通编码定长字符串,长度为10主码,引用Course的外码
Grade成绩小整型取值范围:0~100
要求:

③创建查询每个学生的平均成绩的视图,要求列出学生学号及平均成绩。

考点:计算机等级考试数据库工程师计算机数据库工程师
题型:问答题

按国际商会制定的《2000通则》的规定,下列术语中只能适用于水上运输方式的有 ( )。

A.FCA

B.CIF

C.FOB

D.DDU

题型:问答题

摄影时,散射线主要来源于()

A.相干散射

B.光电效应

C.康普顿效应

D.电子对效应

E.光核反应

题型:问答题

“Keep an eye on Esther. I’ll be back in a second,” Joy Warren said to her three-year-old son Stephen, who was sitting in the back of the Buick. She didn’t like leaving the children alone in the car, but the baby was sleeping soundly. And it would only be a moment.

She had hardly walked 40 yards when she saw the car moving. It headed straight towards the river. Unable to swim, Joy shouted, “My babies are in that car!”

Daniel Whitehead, a 17-year-old student, was walking by the river when the Buick crashed into the water just yards ahead .Without thinking, Daniel jumped in. Though a competitive swimmer, he was shocked by the icy chill.  

Two minutes earlier, Skip Womack had pulled to a halt as the Buick ran in front of him. Now seeing it hit the water and hearing Joy’s cries, Skip got out of his truck and jumped into the water. He had only one thought: If I don’t get them out, they’ll drown.

Daniel reached the car and grabbed a door handle. But the water was only four inches beneath the window, and the door wouldn’t open. With one powerful punch, Daniel and Skip broke a window. Daniel reached inside and lifted Stephen out. He placed him on his back and set out for shore. At the same time, Skip squeezed himself through the window .He managed to free Esther from beneath her seat belt. After he got out of the car with the baby, he held her over the water and swam toward the shore. All this took place just seconds before the Buick disappeared beneath the water.

Later, driving home, Skip thought of his wife and children—how close he’d come to leaving them behind. He thought of the miracle he’d lived through, and how two children were still alive because he and Daniel happened to be in the right place at the right time.

小题1:Why did Joy leave her children in the car?

A.He did not like shopping with a child in hand.

B.She didn’t like waking up her baby.

C.Stephen was big enough to take care of his sister.

D.It was icy cold outside.小题2:Daniel and Skip, who saved the lives of the two kids, _____.

A.had been good friends

B.were two close friends of Joy Warren’s

C.were Joy Warren’s neighbors

D.were strangers before the accident小题3:How did Daniel get Stephen out of danger?

A.He squeezed into the car and carried him out.

B.He pulled him out through the broken window.

C.He freed him from his seatbelt before he got him out.

D.He held him over the water and swam back to shore.小题4:What happened to Joy Warren’s Buick?

A.It had four inches of water in it.

B.One of its windows could not be opened.

C.It was pulled out of water and set on the shore.

D.It sank to the bottom of the river.小题5:How did Skip feel in his way home?

A.He felt lucky to be still alive after having saved the lives of two kids.

B.He missed his wife and children, whom he left behind in the morning.

C.He felt very thankful to Daniel, without whom he would not have made it.

D.He wondered how he and Daniel could be in the right place at the right time.

题型:问答题

空气对运动物体的阻力与物体运动的快慢有关,物体运动的越快受到空气的阻力越大。空降兵离开飞机后,先加速下落,后又匀速下落,从离开飞机到落地这个过程中,空降兵所受合力的变化情况是[ ]

A.一直增大 

B.先减小后增大 

C.先增大后减小 

D.一直减小,直到等于零 

题型:问答题

下表为某地区2008年的人口数。

注1:0~14为少年儿童人口

注2:65以上为老年人口

请据此表计算回答问题:

该地区2008年初人口的平均年龄为()。

A.40.81

B.41.29

C.41.72

D.42.31

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