对树中的一个结点,在先根序列中序号为pre(x),在后根序列中序号为post(x),

题型:单项选择题

问题:

对树中的一个结点,在先根序列中序号为pre(x),在后根序列中序号为post(x),若树中 x是结点y的祖先,下列条件中正确的是 ______。

A.pre(<pre(和post(<post(

B.pre(<pre(和post(>post(

C.pre(>pre(和pos(<post(

D.pre(>pre(和post(>post(

考点:计算机等级考试数据库技术三级数据库技术笔试39
题型:单项选择题

根据短文内容,选择正确答案。

      Peter had a neighbour. His name was Kevin. He was rich (富有的). He loved money very much, and never

gave anything to anybody.

      One day, Kevin went for a walk with his friend near a pond. He slipped (滑倒) and fell into the pond. His

friend ran to help him. His friend held out (伸出) his hand and said, " Give me your hand, and I will pull you

out! " The rich man's head went under the water and then came up again, but he did not give his hand. Again

his friend tried, but again the same thing happened (发生).

      Then Peter came and said, " Take my hand and I will pull you out! " The rich man took his hand at once,

and Peter pulled (拉) him out of the water. " I know my neighbour very well," he said to the rich man's friend,

" You say ' give ' to him, he does nothing. But you say ' take ', he takes! "

1. Kevin ______________.

A. loved to help people

B. never gave anything to anybody

C. was not rich

2. Peter ______________.

A. loved to help people

B. was very rich

C. never gave anything to anybody

3. Kevin ______________ when (当……时候) his friend held out his hand and said, " Give me your hand."

A. did not give his hand

B. gave his hand at once

C. could not hear

4. Kevin ______________ when (当……时候) Peter said, " Take my hand."

A. did not give his hand

B. gave his hand at once

C. could not hear

5. Kevin was ______________.

A. selfish (自私自利的)

B. a miser (守财奴)

C. A and B

题型:单项选择题

— Hurry up, I think it’s going to rain.

— ______ . The skies are dark and cloudy.

A.Not really.

B.I guess so.

C.Why not?

D.How great!

题型:单项选择题

按房地产评估各步骤的代号排序,正常的房地产评估程序应该是( )。(1→选用评估方法估算;2→拟定评估方案;3→明确基本事项;4→实地勘察搜集资料; 5→确定评估结果;6→撰写评估报告。)

A.1、2、3、4、5、6

B.2、3、1、4、5、6

C.3、4、2、1、5、6

D.3、2、4、1、5、6

题型:单项选择题

什么叫虚拟设备?为什么要引进虚拟设备的概念?

题型:单项选择题

河南大学共有两所教育部重点实验室,为面特种功能材料实验室与植物逆境实验室。

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