在火灾事故调查中，公安机关消防机构可以行使哪些职权？

设有一个关系Student(学号，姓名，系名，课程号，成绩)，查询至少选修了四门课程的学生学号、姓名及平时成绩的SELECT语句应该是：
SELECT学号，姓名，AVG(成绩) AS平均成绩
FROM Student
GROUP BY (1)
HAVING (2)

A．COUNT(DISTINCT学号)＞3
B．COUNT(课程号)＞3
C．COUNT(DISTINCT学号)＞=3
D．COUNT(课程号)＞=3

人生的不足和知足（16分）

冯小燕

不管多么优秀的人，总有所不足，有所不能，有所不及。一个政治家不可能处理好改革中的每一个细节，一个科学家不可能精通科学的每一个领域，一个企业家不可能占领每一个市场，一个文学家也不可能写好所有种类的作品，一个旅行家不可能走遍世界的每一个乡村……这就是任何一个人的不足。

‚懂得自己的不足，就会懂得贪图无所不能，只能一无所能；试图无所不知，只能一无所知；企图无所不有，只能一无所有。专心致志地学好做好自己该做的事情，而不是见异思迁、三心二意，就会懂得以“吾日三省吾身”的精神和自觉，常常以人为镜“照差距”，以事为例看不足，以己为训查过错。不断完善自我，修正自我，使自己逐渐成为一个高尚的人，一个脱离了低级趣味、少犯错误的人，一个有益于他人有益于社会的人；就会懂得要成就一番事业，必须借助他人的力量和智慧来延伸你的能力，而不孤芳自赏、自以为是，不能正确地看待自己和周围的人。

ƒ不管多么富有的人，他所享用的物质资源总是有限的。殷纣王“以酒为池，悬肉为林”，但他自己也只有一个普通的胃；秦始皇筑阿房宫，“东西五百步，南北五十丈”，但他自己也只是一个五尺之躯。多么好吃的饕餮之徒，他朵颐之快也必须有间隙，否则就会消化不良。多么生猛的登徒子，他的床笫之欢也必须有节制，否则会肾亏。每一种生理享受都会餍足并严格遵守着过犹不及的法则。这说明                        。

④知足既是一种清醒，更是一种心态。一个人一生的确无需享用过多的东西，明白了这一点就可以善待自己，不必活得那么紧张焦虑。在功名利禄面前，坦然面对各种诱惑；在物欲横流之中保持平常之心、知足之心。这样才会使内心和谐快乐，“看庭前花开花落，任天外云卷云舒”。也正是因为明白了这一点，才可以不抱野心，不怀不切实际的幻想，才能心无旁骛地扛起肩上的职责，尽到自己应尽的本分，踏踏实实地去做成几件事。知道自己需要什么，说明自己在成长；知道自己不需要什么，说明自己在成熟。成功不只是要善于抓机遇，而是要善于放弃诱惑。有所放弃，才能有所收获。每一个人要想有所作为，就要毅然地放弃一切诱惑和不适合自己的目标、计划和行动。

⑤天地悠悠，人生有限。人不可能同时走上两条不同方向的道路，不可能同时拥有春花和秋月，不可能同时拥有明星的鲜花掌声和隐者的清逸自在……总之，不可能把所有好处都占完。知足，就是知生命的缺陷，知人生的“不足”；知“不足”，就是“知足”。

小题1:请用简练的语言归纳本文的中心论点。（3分）

                                                                   

小题2:请根据第ƒ段内容，用简要的语言在空白处补写一句话。（3分）

                                                                       

小题3:第ƒ段运用了什么论证方法？（2分）

                                                                   

小题4:按照议论文“提出问题——分析问题——解决问题”的思路，请你用简要的语言理清思路。（4分）

提出问题：先指出人生有不足，并要认识自己的不足。

分析问题                                                           

解决问题                                                           

小题5:请谈谈你对第⑤段画线句子的理解。（4分）

                                                                    

When you make a mistake, big or small, cherish (珍视) it like it’s the most precious thing in the world, because in some ways, it is.

Most of us feel bad when we make mistakes, beat ourselves up about it, feel like failures, get mad at ourselves.

And that’s only natural. Most of us have been taught from a young age that mistakes are bad, and we should try to avoid mistakes. We’ve been scolded when we make mistakes—at home, school and work. Maybe not always, but probably enough times to make feeling bad about mistakes an unconscious（无意识的）reaction.

Yet without mistakes, we could not learn or grow. If you think about it that way, mistakes should be cherished and celebrated for being one of the most amazing things in the world. They make learning possible; they make growth and improvement possible.

By trial and error—trying things, making mistakes, and learning from those mistakes—we have figured out how to make electric light, to paint the ceiling of the Sistine Chapel, to fly.

Mistakes make walking possible for the smallest toddler, make speech possible, and make works of genius possible.

Think about how we learn：We don’t just consume information about something and instantly know it or know how to do it. You don’t just read about painting，or writing，or computer programming，or baking, or playing the piano, and know how to do them right away. Instead, you get information about something, from reading or from another person or from observing usually...then you construct a model in your mind...then you test it out by trying it in the real world...then you make mistakes...then you revise the model based on the results of your real world experimentation...and repeat, making mistakes, learning from those mistakes, until you’ve pretty much learned how to do something. That’s how we learn as babies and toddlers, and how we learn as adults. Mistakes are how we learn to do something new—because if you succeed at something, it’s probably something you already knew how to do. You haven’t really grown much from that success—at most it’s the last step on your journey, not the whole journey. Most of the journey is made up of mistakes, if it’s a good journey.

So if you value learning，if you value growing and improving，then you should value mistakes. They are amazing things that make a world of brilliance possible.

小题1:Why do most of us feel bad about making mistakes?

A．Because mistakes make us suffer a lot.

B．Because it’s a natural part in our life.

C．Because we’ve been taught so from a young age.

D．Because mistakes have ruined many people’s careers.小题2:According to the passage, what is the right attitude to mistakes?

A．We should try to avoid making mistakes.

B．We should owe great inventions mainly to mistakes.

C．We should treat mistakes as good chances to learn.

D．We should make feeling bad about mistakes an unconscious reaction.小题3:The underlined word “toddler” in Paragraph 6 probably means ________.

A．a small child learning to walk

B．a kindergarten child learning to draw

C．a primary pupil learning to read

D．a school teenager learning to write小题4:We can learn from the passage that ________.

A．most of us can really grow from success

B．growing and improving are based on mistakes

C．we learn to make mistakes by trial and error

D．we read about something and know how to do it right away小题5:What is the best title of this passage?

A．Value Mistakes

B．Mistakes Make Things Possible

C．Try to Avoid Mistakes

D．Life is a Journey Full of Mistakes

现有甲、乙、丙、丁四个相互独立的投资项目，其投资额和净现值见下表(单位：万元)：

方案	甲	乙	丙	丁
投资额	500	550	600	650
净现值	239	246	320	412

由于可供投资的资金只有1800万元，则采用净现值率排序法所得的最佳投资组合方案为( )。

A．项目甲、项目乙和项目丙
B．项目甲、项目乙和项目丁
C．项目甲、项目丙和项目丁
D．项目乙、项目丙和项目丁

研磨机开车前包装岗人员应联系机修人员调整研磨机辊子平行度。