是 两小时内,还是 两小时 后?

我用的单词都比较简单 呵呵 不太认识的你最好查一下词典牛顿；著名物理学家 Newton :Famous physician ,he put forward many great theories in the physics field.维多利亚女王,是英国在位时间最长的君主,Queen Vic...

因为A与B相似,则A与B有相同的特征值,所以,A B的特征值是2 2 y
根据特征值的性质：
λ1*λ2*λ3=|A|
λ1+λ2+λ3=a11+a22+a33
由上述性质得
4y=|A|=6x-6
4+y=1+4+x=5+x
联立方程组解得x=5 y=6

D

利用反证法证明.假设P1•P2•••Pn -1与P1•P2•••Pn +1存在完全平方数,设得到的完全平方数为S^2,那S必然是由2个或者2个以上素数的乘积得到,并且S是偶数（因为最小的素数为2）.也就是说S的因子都是素数,并且分为两组素数,乘积相等并且都等于S.理论上,是不可能存在这样的两组素数,让它们的乘积都相等,因为素数2只能存在于其中一组里面,除了2以外,所有的素数均为奇数,那么一组素数乘积为偶数,一组乘积为奇数,显然不成立.

第一小时是5升和7升
第二小时是16升和8升
剩下的是10升

Working Individually or Working In a Team
There are usually two ways of working:working individually or working in a team.Both of the two ways own their advantages and disadvantages.
Firstly,working individually means that one makes his own plan and settles his own problem.This is more efficient and simpler,because one does all this stuff by himself.This would save many troubles or argues.On the other hand,working in a team might be more interesting and easy.Working in a team means that group members have many discussions together.Thus,some difficulties one cannot overcome might probably solved by his group members.Two heads are better than one.With cooperation,there would be a wonderful solution or propose to the problem.
Personally speaking,I prefer teamwork,because I think working together is a good chance to make good friends with others and to learn about others’ creative thoughts.
June 8,2008
Dear Peter,
I'm glad to receive your letter asking for my advice on how to learn Chinese well.Here’s my advice.
I advocate you to participant in the Chinese courses,for such learning authority can offer you a formal and standard study.In your leisure time,you can read Chinese books or magazines and watch Chinese programs on TV.Besides,learning to sing Chinese songs could be a good way.Also,you may make friends with some native Chinese.And never be afraid of talking to them.Oral Chinese is necessary,which is especially essential to learning a language.And practicing makes perfect.
I hope you can get your answer from my advice!I’m looking forward to see you speaking Chinese fluently!
Yours sincerely,
Li Hua
Dear Sir/Madam,
Greetings from China!I’m Li Hua.I’m a Chinese girl who is extremely fond of pandas since my childhood.I have been very concerned about Sulin and her mother Baiyun,these two cute pandas who in the zoo of San Diego of America.I checked the latest news about them from the relevant website.The little lovely Sulin is going to be three years old.Congratulations to her!Here,I’d also like to present my appreciation to the staff of the zoo.You must be really considerate and hard-working to look after Sulin and Baiyun.Thank you for all your goodness and devotion!
In addition,I do desire to have some photos of these two lovely pandas.Would you mind sending me some?I would appreciate a lot!
Looking forward to hear from you!
Yours sincerely,
Li Hua
Grow up healthily
As we all know,the tragic news about teenagers’ falls or wrongs can be seen in many newspapers.We all feel pity for that.So today,I’d like to advocate strongly that growing up healthily is absolutely important!
To grow up healthily,we need to hold a positive and optimistic attitude toward life.We cultivate ourselves to have strong belief,perseverance,and courage.We are not afraid of failure.Thus we pick up ourselves when we fall down.We encourage ourselves to be tough when faced with difficulties.In addition,we have to work very hard.No pains,no gains.What we earn is as much as what we devote.Hence,we need to be diligent all along our lives.What’s more,sport is necessary in our daily lives.It increases our physical strength and also inspires our mental spirits.We could clear our minds of the daily troubles when we are jogging or swimming.We could also strengthen our friendships when we playing football or badminton.Sports should be accompanied with us lifelong.
In all,to grow up healthily is essential to each of us.We need to hold a positive attitude,to work hard and to do sport.Let’s do it together,and let’s stick to it!Thank you!
We Need Advice from Older Generations
Sometimes,the advice from older generations is really helpful.
I had an experience with my best friend,Tom,when I was in junior school.We planed to work out homework together.Unfortunately,we both insisted our own ways and refused to take the others’.In the end,we lost our temper and got very angry.
I felt very sad and disappointed and we didn’t get in touch for couple of weeks.However,I did cherish Tom as my best friend.Finally I asked help from my father.He was patient and gentle to me.He told me that true friendship is a real treasure.Since I won the true friendship,I should act to maintain it.Father persuaded me to be the first person to break the ice.It was not shameful; instead,it was encouraged and proud.I did as father said.And Tom and I went back to be best friends.We stayed be best friends for almost 10 years.I was very grateful for father helping me to overcome this difficulty.
As the older generations are elder than us,they experienced more than we did.Try to listen to them,they would offer great help!

f(x)=(m,1)*(sinx,cosx)=msinx+cosx
f(π/2)=m=2
所以f(x)=2sinx+cosx
最小正周期T=2π
(2)
f(π/12)=2sin15°+cos15°=√2sinA
AC/BC=sinB/sinA=√6/3
sinB=√6/3*(2sin15°+cos15°)/√2

2*2*pai*0.1=0.4pai

排比

多谢解释了,给你个绝对正宗的吧,有假包换：）
1．90% refundable (10% fee will be charged)[在美生活很多年,很少看到老外会直接说收多少手续费,因为这样会造成消费者厌恶心理,所以lz看情况采用吧] if the ticket is returned 2 hours in advance of departure
20% refundable (20% fee will be charged) if the ticket is returned within 2 hours of departure
50% refundable (50% fee will be charged) if the ticket is returned within 1 hours of departure
2.No ticket is needed for children under 1.2 meters.Half-price ticket is needed for children between 1.2 and 1.5 meters.
.
发车前退90%,可以理解
为什么发车时两小时退80%,这个是发车了,还是没发
能不能把发车过程解释下,不大理解
以便翻译 多谢

5X+Y=5*12
7X+Y=7*10
X=5Y=35
5*2+35=2Z
Z=23

突然一道亮光划破了月夜的幽静,那分明竟是一颗流星.它是那么的耀眼夺目,又是那样的如烟飞逝,当我再次向它凝神一望时,它竟已隐入那暗暗的夜,那样的快急,那样的绝断,一无返顾,丝无恋意.“抹”的一声没了,却激起了我无尽的瑕想,久久挥之不去.不禁想起古龙的名句:“流星追其瞬间辉煌,蝴蝶求其美丽一春”,我不竟痴了.
终于写完了,希望能帮你,不知行不行?

Last sartuday we went to the xian shan motutain to have a picnic.We took several sandwiches and some bottles of water with us for lunch. Of course we didn't forget to take some fruit and we even took some tomatoes and cucumbers.
We left home quite early in order to avoid the traffic jam.About two hours later, we came to a nice place. It was near a river. We put our bicycles under the trees and went swimming. It was a very hot day. The water was very refreshing.
After having a swim, we had lunch in the cool shade under the trees. Then we went for a walk. We didn't come back home until the night fell.

其实,in个人理解,只有一种意思,如果要是刻意想要强调之内,一般都会用within的.如果只用了in ,意思就是未来的某个时间段之内会发生什么,你也可以理解为某个时间段之后马上发生,但是这两者有多大区别呢?
I will come back in 2 hours 其实就是中文的 “我两个小时就回来” 所以LZ觉得到底是以内呢还是之后呢?哈哈哈
这种问题没必要较真的~因为本来很正式的说法中就不会单独用in表示这种意思的~

Many companies recently claimed, let its employees take the speed-reading course will make their work efficiency is greatly improved. One who can read a 500 page report in two hours. One who less than a year was promoted from assistant manager to ceo. Obviously, a person to read faster, the amount of information he obtained within a working day is more. Moreover, fast read costs only $500 per employee. Considering that it will bring to the company profit, this item of expenditure is not worth mentioning. Obviously, if the company requires all employees take the speed-reading course, will benefit greatly.

What's wrong with you?
I'm sorry to hear that.
I'll go with you.
Don't worry.
Will she help me with my lessons?

很乐意为你解答这个问题!
首先要清楚must,can,should ,may,might 等等情态动词后面动词一定要用原型,也就是说must无论是做“猜测”还是“必须”的意思,后面一定是跟动词原形的.也就是说must have been是正确的说法.而你所提到的must had been是不存在的.我明白你是为了强调是过去的时态,但是在语法中must have been 就可以表示在过去时态下的意义.
例如：I thought he must have been at home last night.就表示：我认为他昨晚一定在家.
.

牛吃草问题
12×3=36（个）
8×5=40（个）
（40-36）÷（5-3）=2（人）
36-2×3=30（个）
30÷2=15（人）
15+2=17（人）

第一小时候卖了桶10升.
第二小时候卖了5.7.8升.
剩下16升.
(5+7+8)/10=2

1.
设重叠使高度增加为A
单个碗摆放高度为H
H + 4A =10.5
H + 6A = 15
解得 A = 2.25
H = 1.5
Y = 1.5 +(X-1)*2.25
2.
代入 X =12
得Y = 26.25
PS:单个碗高度 比重叠增加高度还少
好象数据有问题呢.
解答仅供参考 希望更强的人来说说

直角坐标系下：
D = {(x,y) | (x^2+y^2)≤1 ,|x| ≤ y } ∪ {(x,y) | (x^2+y^2)≤4 ,y ≤ -|x| }
极坐标系下：
D = {(r,θ) | r≤1 ,π/4≤θ≤3π/4 } ∪ {(r,θ) | r≤2 ,5π/4≤θ≤7π/4 }

You can't eat anything within the next two hours.
天上~

你不但要好好学习,还应该注意身体.

草,虽然平凡、渺小,但却有坚韧不拔的生命力；虽然不美丽,但却具有极其旺盛的生命力；这一切都是对生命的渴望而得来的力量!草,不管闪电雷击,不管狂风骤雨,不管严寒酷暑,它都毫不畏惧.这一切都是信念的力量,小草渴望生命,渴望生存,于是又站了起来!
我漫步在小路上,看着路旁那一棵棵嫩绿葱郁的小草,陷入了沉思……
也许,有很多人都把小草当成是弱小、无能的象征,认为它们那矮小的身躯经不起一点儿风雨.但,我却不这么认为,因为在我眼里的小草,是那样的顽强,那样的富有生机,而最重要的一点,是它们本身具有的生命力和精神!
一到春天,小草们就睁开朦胧的双眼,争先恐后地破土而出,与人们一同分享春姑娘所带来的喜悦与温暖.它们散满大地,为这块抚养它们的“母土”铺上了绿地毯……这千千万万的小草组合起来,才让人们看到了生命的伟大.
当然,小草的可敬之处不单单是在这里,它们身上还闪耀着一个亮点——顽强不屈的精神.小草虽然没有参天大树那样的高大挺拔,也没有花朵那样的鲜红美丽,但是,它们的精神足以盖过这一切,足以让人们重新去认识并惊叹它们.
暴风雨里,高大挺拔的大树被连根拔起,五颜六色的花朵已花残叶败,而小草呢,却以一种比物质的力量更加有力的力量赢得了胜利……等到暴风雨过后,花树都变了样,只有小草依然昂首挺胸地站在那儿,享受着雨后的阳光……正因为此,它们才对得起大诗人的一句“野火烧不尽,春风吹又生”.
我想：在漫长的人生旅途中,人人都会遇到崎岖与坎坷,只要我们具有小草的精神,绝望之云终会驱散,希望之花将会常开.我永远不会忘记那一丛新生的小草,更不会忘记妈妈满含期望的笑脸![ ①小林]

Dear,
Thank you for your letter.
We are very interested in your products,but i have to say that the price you give me was too expensive than i can accept.
To be honest,i had contact with the other seller,and their price is much better than yours.You know we often receive many letters from the sellers,and everyone of them said they can provide their products with good quality and competitive price.But what we want is a seller who can establish business relations with us and become our regular seller,and get a win-win situation.I hope you can give me your best price,if not that will make no sense.
Your early reply is appreciated.
Sincerely,
Your name
note:just for your reference.

设OB=OC=m,OA=2m
点A(-2m,0)
点B(m,0)
点C(0,m)
带入得
am2＋bm＋m＝0 ①
4am2－2bm＋m＝0 ②
②－4×①＝－6bm－3m＝0
约一下
2bm＋m＝0
所以b＝－1/2

15.5减5等于10.5元

尽管不是很容易做到,我们还是在两个小时内开车回到了家 （没有只能的意思,就是已经这么做到了）
希望对你有帮助哦O(∩_∩)O~

You can't eat anything in two hours

2年级一班的同学们在没有老师督促的情况下正专心致致地在宽敞明亮的自习室做作业.

1.为了打得方便,设浮力F,密度为p.F=G/4
F p液*V/2*g
- = ----------
G p球*V*g
F/G=1:4
所以
p球：p液=2：1
2.因为悬浮
所以F=G=0.5N
球的平均P=水的密度
V=M/P=50cm3
设空心体积为V2
P铁（50-V2)=50g
忘记铁的密度了,自己摁计算器
不懂再问

①f(0)+f(0)=f(0),f(0)=0
f(x)+f(-x)=f[x+(-x)]=f(0)=0,f(-x)=-f(x),f(x)是奇函数.
②设x1f(x2).
所以f(x)单调递减.
③f(2-2cosx)+f(sin^2 x-m)

I did not think much about this question before.I think I can go on with my present research,or do some similar research under your direction,

within two hours after born

Nowadays,more and more people prefer to remain single,no matter it is a man or a lady.Perhaps,it is just because of the social development.People would not like to have much more responsibility on themselves.In another word,it is ,perhaps,due to the social pressure.People are afraid of marriage and children-raising.Mainly because it is not easy for people to find an ideal job,and to earn enough money to support the family.Meanwhile,some people are afraid of failure,especially the failure in marriage.Everybody knows that the attitude towards marriage now is changing.It is much easier for people to make new friends with the development of the modern science,such as,mobile phone and internet.Therefore,it is much easier for people to get devoice.

你矩形的后院（的长）是宽的两倍,你把后院用240英尺的栅栏围了起来.你想给你的后院施肥.每袋肥料可以覆盖2000平方英尺.你需要买多少代肥料.解释你的答案

寂寞时,不打游戏,不看电影,沉浸在知识的海洋里,书香四溢.
郁闷时,不发牢骚,不碰烟酒,飞翔在神奇的殿堂里,妙笔生花.
吮吸着它,消化着它,升华着我.
捧着它,闻着它,看着它,望着它,凝结着智慧的结晶,滋润着学子的心灵.
它无处不在,一时躺在纸上,一时躲在网里,一时隐在万物中,时隐时现,欲露还羞.
不管你在哪,我都能感觉到你对我的注目.
寻找着你,追逐着你,呼唤着你,一路劈风斩浪,百折不回.
深情的拥抱着你,你却说：“光拥有是不够的,关键是能用出来,否则,你就是个书呆子.”

|a|-1
所以
ab+bc+ac
=f(a)>{f(-1),f(1)}min>-1