有三个关系R、S和T如下:则由关系R和S得到关系T的操作是()。 A.自然连接 B.

题型:单项选择题

问题:

有三个关系R、S和T如下:

则由关系R和S得到关系T的操作是()。

A.自然连接

B.交

C.除

D.并

考点:计算机等级考试JAVA二级JAVA笔试
题型:单项选择题

重新排列下列语段,把它们组成一篇连贯的短文。

     (A)Lana asked for a job in a TV station. She was asked to meet Mr. Baker, the manager, at 9∶00 a.m. in

his office.

     (B)To her surprise, he seemed pleased with her. She was even more surprised when he asked her if she

could start the work soon. It seemed she had got the job at last.

     (C)"I may not get the job," Lana said to herself. Just then, Mr. Baker came through the door and hurried

into his office.

     (D) "You've never worked in a TV station before, have you?" he asked. Lana felt upset and answered no.

Now she was even more sure that she would not get the job. Then Mr. Baker asked her some other questions.

     (E)A moment later, the secretary took Lana in. Lana said sorry for being late. Mr. Baker did not seem to

mind. He took out her letter for the job and studied it.

     (F)Lana was a few minutes late. Mr. Baker wasn't in the office when she got there. His secretary told her

to wait outside the office.

The right order is: 第一段A 1._____ 2._____ 3._____ 4._____ 5._____

题型:单项选择题

下列各项表述正确的是

A.次氯酸的电子式:

B.表示中和热的热化学方程式:NaOH(aq)+HF(aq)=NaF(aq)+H2O(l)△H=-57.3kJ/mol

C.H2S电离的方程式为:H2S 2H++S2-

D.标准状况下,1.12L16O2和1.12L18O2均含有0.1NA个氧原子

题型:单项选择题

在真脏脉中,主脾肾阳气衰败,提示神气涣散,生命即将告终的脉象是()。

A.弹石脉

B.转豆脉

C.偃刀脉

D.屋漏脉

E.鱼翔脉

题型:单项选择题

混合农业与商品谷物农业共同特点是商品率高

题型:单项选择题

2007年9月1日某公司由于承担国家游泳场重要工程项目,经批准免税进口了一套机械施工设备。项目完工,公司于2008年9月14日公司将该设备出售给了国内另一家企业。该设备的到岸价格为1300万元,关税税率为10%,海关规定的监管年限为5年,按规定公司应补缴关税( )万元。

A.10.2.23

B.103.36

C.104

D.106.17

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