若齐次线性方程组只有零解,则它的系数行列式等于零。
向量α=(1, 0,-3, 5),β=(4,-2, 0, 1),则其內积为__
Ax=0,A是3×4阶矩阵,基础解系中含有1个向量,则R(A)=( )
n阶矩阵与对角矩阵相似的充分必要条件是( )
B.

有n个不全相同的特征值
已知三阶方阵A的三个特征值为-2,3,4,则的特征值为
The author felt excited when her family won a free photographic portrait sitting, because she could wear the same blue uniform as her peers and would not be made to stand on the stage.
Listen to the text and decide which of the following best states the author's purpose.浏览器不支持音频
A.
To give an account of the author's hard life at home and at school during the Second World War.
B.
To illustrate that words of compassion in times of need enable a person to regain his confidence and exert a lasting influence.
C.
To present a picture of different teachers at her school.
The author hoped that her parents would be more protective and speak to the deputy headmistress on her behalf.
Because of her father's ingenuity and mother's thrift, the author's parents could manage to support the family and keep their children well-fed and decently clothed in school.
There is the most ________ dress on sale at the shop!
They tried to _________ him for losing the prize by taking him to a theatre.
Her face showed her ________ at missing the party.
Why have you __________ this incident for adverse comment?
What does the word "mean-spirited" mean in the sentence "And then she came out with the most welcome sentence I had ever heard at that mean-spirited place."?
Compared with other writings that were also experimental and revolutionary in history, online writings are not only large in quantity, but good in quality as well.
When engaged in online writing, professional writers can always make themselves welcome without catering to the fashion of the new medium.
The product will have to meet internationally ________ standards.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
To the ________ of the show’s organizers, the top performers withdrew at the last minute.
E-mail and computer conferencing demonstrate to a whole generation of people that the language we use does not have to be always so formal as in traditional letter writing.
It could be inferred that people who produce netwriting are from different walks of life.
Passage OneQuestions 1 to 5 are based on the following passage.Texting has long been bemoaned (哀叹) as the downfall of the written word, “penmanship for illiterates,” as one critic called it. To which ...
The presentation was a __________ effort by all the children in the class.
Some students ________ the composition in ten minutes in the final-term examination.
New computer systems have made old methods of data processing _________.
What does the word "intoxication" mean in the sentence "The feeling of intoxication that followed her victory was cut short by her father’s sudden death."?
He’s always _________ to his childhood and saying how things were better then.
You will probably be asked about whether you partake in very _______ sports.
Unfortunately, a great many people lack even that _________ level of security awareness.
The parents who recognize their children’s incapability to make the cut have never expected their children to go to prestigious universities.
Passage OneQuestions 1 to 5 are based on the following passage.It’s possible to admire Oprah Winfrey and still wish Harvard hadn’t awarded her an honorary doctor of law degree and the commencement(毕业典...
The author’s success as a freelance writer is largely due to his education in a prestigious university.
The only________came from a small window high in the oppositewall.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
The lives of thousands of birds are _______ as a result of the oil spillage.
The medical examination before you start work is __________.
The campus tour of MIT enabled the author to change his attitude about college selection.
What does the phrase "taking their toll" mean in the sentence "Seventeen years of unread textbooks, unvisited museums, and untaken AP courses are now finally taking their toll ...."?
C.
having a little effect
Hissonhada(n)_________drivetogainhisfather'sapproval.
Herhumouranddeterminationwereasourceof _________toothers.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
Superstition is prevalent because it can meet people’s curiosity about their future.
The past two years have seen a ________ of TV channels.
She claimed that the rise in unemployment was just a further ________ of the government's incompetence.
A majority of temples and Pagoda are in _________ conditions and are in dire need of urgent repair lest they fall down
What he did was __________ of acceptable behavior.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
Passage OneQuestions 1 to 5 are based on the following passage.Technology can make us smarter or stupider, and we need to develop a set of principles to guide our everyday behavior and make sure that ...
The author implies that American people, both men and women, are not so readily aware of the existence of prejudice against women as that against blacks.
The author’s experiences of running for office indicate that her every attempt to go upward in politics was met with men’s strong disapproval.
There is a ________ of people with an arts degree on the board of governors.
Passage OneQuestions 1 to 5 are based on the following passage.America's recent history has been a persistent tilt to the West--of people, ideas, commerce and even political power. California and Texa...
Being able to express compassion, patience, love, and understanding for the people in our families, despite opposing views belief systems, allows us to expand our ability to ________ with others.
According to the author, her major responsibility in politics is to affirm the role of women in the country.
Rescue efforts have been __________ by rough seas and hurricane-force winds.
That there is prejudice against women is an idea that still _______ nearly all men -- and,I am afraid, most women -- as bizarre.
His feelings of resentment have been _________ for years.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
The author’s experience in hospital serves as a reminder that beauty is everywhere in our daily life, but we often fail to appreciate it.
Women find they cannot ________the needs of family life with the needs of their employment.
She has compaigned ________ for her husband's release from prison.
Passage OneQuestions 1 to 5 are based on the following passage.“Deep reading”—as opposed to the often superficial reading we do on the Web—is an endangered practice, one we ought to take steps to pres...
You must keep things________ the overall situation isn't really that bad.
It's important to store __________ food in a cool place.
Why fashion things of beauty when beauty is ________ ?
With a few exceptions, most of the author’s ancestors lived to a great age.
Lately, his ________ with football had caused his marks at school to slip.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
The population will get much older in the coming decades, but the public pension scheme is still in its _________.
If you left your grown-up children alone, they would become very callous because of your indifference.
It is obvious that those who do not have strong impersonal interests will unduly concern themselves with their children and grandchildren to fill the void in their lives.
I never do anything whatever on the grounds that it is good for health, though in actual fact the things I like doing are mostly __________.
Passage OneQuestions 1 to 5 are based on the following passage.Many current discussions of immigration issues talk about immigrants in general, as if they were abstract people in an abstract world. Bu...
The author is very particular about his diet and careful in his lifestyle.
And if, with the decay of vitality, ________ increases, the thought of rest will not be unwelcome.
SECTION B INTERVIEWIn this section you will hear everything ONCE ONLY. Listen carefully and then answer the questions that follow. Mark the correct answer to each question on your answer sheet.Questio...
根据煤化程度的不同,腐殖煤可以分为泥炭、褐煤、长焰煤和无烟煤。
直接顶是直接位于煤层之上的岩层,由较易跨落的一层或几层岩石组成,采动后随回柱而自行垮落,有时需人工放顶。
基本底位于直接底之下,也有直接位于煤层之下,一般由比较坚硬稳定的砂岩、石灰岩组成。
Passage OneQuestions 1 to 5 are based on the following passage.It is easy to miss amid the day-to-day headlines of global economic recession, but there is a less obvious kind of social upheaval(剧变)und...
为便于煤炭地质勘查和煤矿生产的应用,依据煤层的结构,可将煤层厚度划分为总厚度、有益厚度和最低可采厚度。
煤层总厚度是煤层顶底板之间各煤分层厚度之和,夹石层厚度不算在内。
可采厚度是指在现代经济技术条件下可以开采的煤层的厚度或煤分层的厚度总和。
根据煤层形状在一个井田范围内成层的连续程度和可采面积与不可采面积之比,将煤层形态分为哪几类?
煤工业分类主要目的是有利于煤炭资源的合理开发、利用和满足用户的生产要求。
煤工业分类的意义有哪些
A.
是统计资源储量和评价煤炭资源利用合理性的根本依据
B.
是反映国家在煤炭加工利用方面的科学技术水平的指南