抗炎抗肝纤维化药物为( ) A．秋水仙碱 B．螺内酯 C．右旋糖酐 D．心得安 E

基于“学生一选课一课程”数据库中的三个关系：

S(S#，SNAME，SEX，AGE，DEPARTMENT)主码是S#

C(C#，CNAME，TEACHER)主码是C#

SC(S#，C#，GRADE)主码是(S#，C#)

为了便于识别，当外键与相应的主键属于不同关系时，往往给它们以相同的名字。

下列扩展的关系操作中，哪些是正确的？（）

Ⅰ．在关系C中，增加一门课程(‘C06’，‘电子商务’，‘陈伟钢’)，可以用赋值操作表示为：C←∪｛(‘C06’，‘电子商务’，‘陈伟钢’)｝

Ⅱ．关系SC中删除学号为‘20100251’同学的信息，用赋值操作可以表示为：

SC←SC-(σS#=’20100251’(SC)

Ⅲ.计算年龄小于20岁的学生人数，用聚集操作表示为：

Gcount(S#)(σAGE<=20(S))

Ⅳ.计算课程号为‘C01’课程的平均成绩，用聚集操作表示为：

Gavg(GRADE)(σC#=’C01’(SC)

A．仅Ⅰ、Ⅱ和Ⅲ

B．仅Ⅰ和Ⅱ

C．仅Ⅱ工和Ⅳ

D．都正确

地球赤道周长约            千米。

胸壁缺损直径2cm会发生（）

A.颈静脉怒张

B.左肺呼吸音减弱，叩浊，腋下可闻及肠鸣音

C.纵隔扑动

D.胸壁反常呼吸运动

E.头面颈部肿胀、发绀、出血

现阶段网络计划优化的目标有______。

A．按资源有限优化工程质量

B．按合同工期缩短关键线路

C．按工期最短优化资源均衡

D．按费用最低优化有限资源

E．进行工程费用优化

阅读理解。

     Feb.3,2006-According to CCTV 4,Chinese scientists have recently taken the lead in building the first

full super-conducting experimental nuclear fusion (核聚变) device known  as"artificial sun"in the world,

which will produce energy like the sun.

    It is reported that this device consists of five layers of components(成分)from inside to outside and the

circulating magnet container in the innermost layer looks like a giant" swim ring". In experimental tests,the

temperature of inner" swim ring" will reach as high as 100 million degrees Celsius. Therefore,such

component is a significant part to stimulate solar fusion reactions.

    Wan Yuanxi,who is in charge of the project called Experimental Advanced Super-conducting

Tokamak( EAST) ,an important scientific project under China's ninth five-ycar plan,explained the reason

why the sun always gives off light and why the energy it produces will not decrease. Under high pressure

and high temperature, fusion reactions will take place from inside to outside of the sun.

     Such fusion reactions will give rise to a great deal of energy to enable the sun to continuously emit light

and heat. However,fusion reactions on the sun are uncontrollable,just like an H-bomb explosion seen on

the earth. A huge amount of energy will be produced in a minute,which may be destructive. In order to

make use of such energy,a transformation from the process of energy production to a stable,sustainable

and controllable process is needed. EAST is serving to initiate such a transformation. Under magnetic

force,the op-

eration of hydrogen plasma isotope (同位素) will be restrained in the" swim ring" and high density

collision will happen, namely the fusion reactions. The hydrogen isotope got from one liter of seawater

can produce energy equal to 300 liters of gasoline through complete fusion reactions.

    Wan said that we can get endless clean energy by producing such a device for accomplishing fusion

reactions,which is equal to one or a few small suns made by human beings themselves so that they can

ceaselessly obtain energy from nuclear fusions.

1. What's the best title for the passage?

A. Wan Yuanxi and His Invention.

B. The Sun and the" Artificial Sun".

C. How to Produce the" Artificial Sun".

D. China Built the World's First"Artificial Sun".

2. What does the underlined word" artificial". ( in Para. 1 ) mean?

A. Not real.                        

B. Man-made.

C. Actual.                          

D. Ancient.

3. Which of the following is NOT true?  

A. The temperature of the innermost part of the " artificial sun" will reach as high as 100 ,000 ,000?.

B. EAST is an important scientific project under China's ninth five-year plan.

C. Such fusion reactions in the" artificial sun" will give us limited energy.

D. The hydrogen isotope got from one liter of seawater can produce energy equal

     to 300 liters of gasoline through complete fusion reactions.

4. What's the purpose of making the" artificial sun" ?     

A. To get more energy.

B. To get more light.

C. To have the sun shining for us in 24 hours

D. To study the inside of the real sun.