救急；简单的高一集合问题.下列命题正确的有：1.｛0,3｝是一个集合.2.｛0,3｝是集合｛｛1,2｝,｛0,3｝｝的一

1楼不全面
1 点在圆上(点到半径的距离等于半径)
点在圆外(点到半径的距离大于半径)
点在圆内(点到半径的距离小于半径)
2 (1)相切:圆心到直线的距离等于半径
(2)相交:圆心到直线的距离小于半径
(3)相离:圆心到直线的距离大于半径
3 圆的切线是指 垂直于半径,直线到圆心距离等于半径的直线,垂足叫切点
4 圆心距为Q 大圆半径为R 小圆半径为r
两圆外切 Q=R+r
两圆内切 Q=R-r (用大减小)
两圆相交 QR+r
两圆内含 Q

As everybody knows,Internet is a very important part of our life.But for the teenagers,it's not always good.Internet is a double-edged sword.There is lots of information on the Interenet.So it's a very helpful tool for students to get information swiftly and easily.However,some information is good and some may be bad.So for the teenagers,it's important to find out the good things and keep the bad things away.But most teenagers haven't got such good self-contral.So,if someone young is surfing on the Internet,it's a good idea to use the"Green Dam".

what do we do next
what to do next

地球的内部可能极为的“不安分”,蕴含着极大的能量,想火山喷发,地震等

老师我想对您说,有时我们不懂事在课堂上总是惹您生气,深感对不起您.
有时在课堂上,有些同学在说悄悄话,您看见了就用目光提示他们,让他们注意,别讲话,仔细听讲,否则学不到知识,那些说悄悄话的立刻闭上嘴,仔细听讲.
每次您上课时,您会从走廊上慢慢地走来,同学们听到您的脚步声,马上安静下来,等待您的到来.每当下课时您会对我们像吃了蜂蜜一样的微笑,来给我们说笑.
由于有了您的辛勤的付出,我们班从三年的级的最后一名,提升到了第三名.您为我们操了不少的心啊!照您这样教我们,我们一定会赢得第一名的.
放学后,我们回家做完作业,在阳台上欣赏美丽的风景,看着天空的星星,而您呢?还在屋子里辛苦的为我们批改作业.想快点改完作业,早点睡觉.第二天要来给我们上课.有时侯,我们不懂事,惹您生气了,让您头上的白发似乎又多了几丝银发.
亲爱的老师,我想对您说：“您辛苦了,您劳累,我们让您操心了,让您头发染上了银丝……”
老师,我们一定会用优异的成绩来报答您的,决不会让您失望.
1.时光荏苒,转眼之间,二十年了,老师你还好吗?
老师,我想对你说：你的音容笑貌,你的举手投足,时常展现在我的眼前；你的关心,爱护,一直萦绕在我的脑海里；你的循循善诱,谆谆教导,至今铭记在我的心中；你和我们一起时的一切,都如同昨日历历在目.
老师,我想对你说：是你给了我学习的自信；是你给了我生活的勇气,是你给了我发奋发图强的动力,是你给了我奔向好前程的希望.
老师,我想对你说：你是我开启智慧的敲门砖；你是我打开幸福之门的金钥匙；你是我生活航程中的引路人；你是我奏响人生乐章的指挥者.
老师,我想对你说：如果没有你,或许我就会自暴自弃；如果没有你,或许我就会那么沉迷下去；如果没有你,或许就没有我生活的前景；如果没有你,或许就没有今天的我.
老师,我想对你说：感谢你风雨之中为我的遮挡；感谢你冰天雪地之时给予我温暖；感谢你对我的培育之恩；感谢你对我的知遇之情.
老师,我想对你说：新年到了,祝愿你健健康康,幸幸福福,和和美美,快乐乐地度过每天!好人一生平安!
2.老师,你会说英语、会有情感地朗读文章,会唱动听的歌曲,会画画,还会算难度很高的数学题,会……但你有一样不怎么会,而且是最重要的一点——笑.
你每天扳着脸走上讲台,我们刚下课玩后的愉快心情又被破坏了.这时我多么希望你能笑一笑啊!开始上课了,你一直眉头紧锁,忽然叫起一个正在开小差的同学回答问题,那个同学丈二和尚摸不着头脑,答得牛头不对马嘴.老师顿时火冒三丈,问他怎么回事.“后面的同学告诉我的”,全班哄堂大笑,但老师不笑,仍然眉头深锁,用箭一样的目光盯着我们,我们只好马上闭上嘴巴,正襟危坐.这时,我们多么希望老师你也能笑一笑啊!这样,你的不快、同学们的不认真,也许就会在一笑之中飘然而去,我们与你的距离会因这一笑而变得亲近起来.
下课了,有很多同学跑上讲台,想跟你谈谈话,可一头忙碌的你一句：“什么事?”正欲张嘴的我们不好意思开口了.那时,我们多想你笑着与我们放松地聊一聊啊!
“笑一笑,十年少,我们学习会更好；笑一笑,真轻松,苦恼、伤心抛脑后.”我以前也写过这样的儿歌或小诗,但都没敢唱,什么时候能在你面前开心地唱一唱呢?
老师,我们知道你严厉是为了我们好,我们经常会惹你生气,但如果你时时刻刻都调整好心情的话,这点小事你不会在意的.
今后,我们会好好地学习,拿出良好的表现和最好的成绩给老师看,让老师开心,让老师微笑!
3.（诗歌形式,
你说红苹果是果树,
吹出的泡泡
是一颗颗彩色的小太阳.
老师,我想对你说,
你是魔术师,
你托起了一个神奇的梦想.
你说孩子头上的蝴蝶结
是会转的螺旋桨.
于是那个爱美的小姑娘,
幻想有一天能飞到天上.
老师,我想对你说,
你是天使,
你洒下了一片青春和阳光.
你说向日葵是朝鲜族小姑娘,
头上顶着金黄金黄的洗脸盆儿,
笑微微地等待着
田野里归来的农民伯伯
洗一洗晒黑的脸庞.
老师,我想对你说,
你是园丁,
你播下的是种子和希望.
你说月儿光着脑袋,
没戴棉帽,
旁边两颗星星是冻红的耳朵,
他有一位狠心的后娘……
于是那个爱淘气的小男孩,
摘下滑冰帽,
眼泪汪汪……
老师,
你是圣洁的安琪儿,
你已经撒下了憧憬和想象.
老师啊,我想对你说,
在孩子中间,
你是想象的风,
你是幻想的旗,
率领着天真,
率领着勇敢,
荡起如云的秋千,
登上开满鲜花的山岗……

the following orders request all suppliers to deliver next Monday.
Prices of all items will be same as the former purchase price ,pls help to check & approve.

desk case

倒装句：
金溪民方仲永,世隶耕
省略句：
不使（之）学
倒装句：
还自扬州（正确语序是“自扬州还”）

设开始时左端的空气压强为P1,显然,
P1=Po+ρ水银*g*h
当管子自由下落时,高度为h的水银柱不再产生压强了(自由落体运动是一种完全失重运动,所以,水银柱不再对底面产生压强了)
这样,右端水银面将会继续上升,设稳定时左端又下降了h',这样右端比左端高了:(h+2h')
稳定时,管内的空气压强等于大气压Po,空气柱的长度为(h+h')
根据波意尔定律:
(Po+ρ水银*g*h)*L=Po*(L+h')
解出,h'=ρ水银*g*h*L/Po
这样,两边水银的高度差为h+2h'=h+2*ρ水银*g*h*L/Po=h(1+2*ρ水银*g*L/Po)

设有x个教师参加旅游,甲旅行社收费为y1元,乙旅行社收费为y2元,由题意得,
y1=0.75*1200（x-1）+1200=900x+300
y2=0.8*1200(x-1)=960x-960
由y1小于y2得,900x+300小于960x-960
得x大于21
答：略

All (of you) are proteins(可数）.

Cl2+H2O=HCl+HClO HCl+AgNO3=AgCl（沉淀）+HNO3 AgCl+Cl-=AgCl2- 追问： 氯酸·水· 硝酸银 的反应吗 回答： 是说 次氯酸 （HClO）吧!与硝酸银的反应我也没有见过.

本题稍加分析,就能发现：要到达棋盘上的一个点,只能从左边过来或是从上面下来,所以根据加法原理,到达某一点的路径数目,等于到达其相邻上,左两点的路径数目之和,因此我们可以使用逐列（或逐行）递推的方法来求出从起始顶点到重点的路径数目,即使有障碍（我们将马的控制点称为障碍）,这一方法也完全适用,只要将到达该点的路径数目置为0即可,用F[i,j]表示到达点(i,j)的路径数目,g[i,j]表示点(i,j)有无障碍,递推方程如下：
F[0,0] = 1
F[i,j] = 0 { g[x,y] = 1 }
F[i,0] = F[i-1,0] {i > 0,g[x,y] = 0}
F[0,j] = F[0,j-1] {j > 0,g[x,y] = 0}
F[i,j] = F[i-1,j] + F[i,j-1] {i > 0,j > 0,g[x,y] = 0}
本题与第三题一样,也要考虑精度问题,当n,m都很大时,可能会超过MaxLongInt,所以要使用Comp类型计数(Comp类型已经足够了,即使n=20,m=20,没有任何障碍的情况下的结果也只有14,5位的样子).

early to bed,early to rise,
早睡早起
make a man healthy,wealthy and
让一个人身心健康又有钱
a father of a big fimaly...
有是一家之长
连起来就是
早睡早起会让一个（男）人身心健康又能挣到钱/又富有,而且还是一家之长.
family你写错了是family不是fimaly

由 (2a-c) Cos B=b Cos C 得a^2+c^2-ac=b^2 ----B=60度
m*n=根号下2（2A+π） 可求得A值
B角有用,用来确定A的范围 2π/3-A﹥0

(1)确定定义域,
（2）根据定义,设X1 X2 ,f(X1) f(X2) 确定不等式的方向是否一致,一致则单调性一致
（2）根据导数知识,很容易确定单调性.（2）奇偶性在解题过程中也可以使用·
XX 一些特殊,常用函数,单调性要记住.
当然,两大思路就是定义和导数,自己要变通,选择好方法.
单调性是函数的一大核心.

HalloweenHalloween is an autumn holiday that Americans celebrate every year.It means "holy evening," and it comes every October 31,the evening before All Saints' Day.However,it is not really a church ...

Hi！（好啊） My name is chenjie。（我的名字叫陈洁） I‘m (年龄)years old 。（我今年x岁） I'm friendly to everyone,so many people like me . （我对人很友好，所以很多人都喜欢我）。 I'm (身高)cm tall。（我有xcm高） I’m very lovely，too！（我也很可爱） My favourite subject is English . and i like sports very much . （我最喜欢的科目是英语，而且我很喜欢运动） English brings lots of fun . and sports makse me happy .（英语带给我很多乐趣，而且运动使我快乐） I like this sentence:“ nothing is impossible。”（我最喜欢的一句话就是：一切皆有可能。） So i always try my best to do everything well,and never give up easily.(所以我每一次总是尽力做好每一件事情，从来都不轻易说放弃） So this is me ,i hope to make friends with you all.（这就是我，我希望和大家都能成为朋友。） （改成自己就好，请采纳）

延长CB,DE,相交于点F
因为AD平行CF
所以角DAE=角EBF
因为点E平分AB
所以AE=EB
因为角EBF=角EAD（对顶角相等）
所以三角形ADE全等于三角形BFE（ASA）
所以BF=AD
因为AD+BC=CD CF=CB+BF
所以CF=CD
又因为三角形ADE全等于三角形BFE
所以ED=EF
所以CE为DF的中线
所以CE垂直DF（等腰三角形三线合一）
所以角CED=90度
数学爱好者手打原创,

去找一篇游记，把它地点和景色改一下，perfect

x(x+1)=3(x+1)
x²+x=3x+3
x²-2x-3=0
(x-3)(x+1)=0
x=3或x=-1

这个星期,我调查了学生关于时尚的话题.我给每个学生6件东西,问他们关于每一件东西的一些问题.他们的回答中有一些十分有趣.这里使他们喜欢的和不喜欢的：
Judy Smith喜欢钥匙圈.她的朋友Jack说他不能忍受围巾.“那是妈妈带的!”他说.William Jones 热爱皮夹,他的同学Gina Taylor热爱手表.（她最好的朋友Ann Rice对手表不是很介意,但是她十分喜欢太阳镜!）Jerry也喜欢太阳镜.

advertise
advertisement
be used to
share
persuasive
image
product
service
billboard
promote
place
intended
educate
issue
welfare
complete
law
lie
untrue
claim
aware
be aware of
even if
toothpaste
breath
bad breath
advertiser
cure
customer
comment
connect
fall for
trick
play tricks on
original
creative
public
nationwide
campaign
drug
deal
deal with
social
slogan
school
live
smoking
commit
commit suicide
suicide
smart
complete
satisfied
be satisfied with
schoolmate
trick
trick sb into doing sth
publisher
reader
unique
imagination
fascinating
over and over again
category
senior
senior high
choice
recommend
purchase
copy
sales
bar
ice cream
repackaging
eye-catching
company
update
packaging
in order to
old-fashioned
design
feature
completely
commercial
sweet
soft drink
unforgettable
fashionable
convenient
continuously
cute
height
up to
functional
filling
finger-licking
funky
bored
be bored with
jeans
day and night
available
build
various
particular
audience
goal
target
media
mailing
determine
extremely
appeal
appeal to
react
gather
be concerned with
get sth across
put sth together
approach
sporting
honourable
delighted
significance
briefly
discus
wresting
running
athlete
compete
unmarried
take part(in)
separate
honourable
in honour of
god
restart
peacefully
side by side
well-known
boxor
medal
gladly
light
flame
ceremony
opening ceremony
superstar
scorer
distance runner
record
break the record
running
contribution
make contribution to
absense
female
table tennis
excite
Asian
hurdle
Olympian
joy
attempt
limit
movement
glorious
international
committee
state
retire
host
facillity
stadium
first-class
itself
plenty of
transport
attaction
tourist atrraction
bid
fan
pretty
coach
warm-up
otherwise
swimmer
post
centimetre
net
stretch
court
origin
outdoors
version
physical
technique
opponent
leading
role
play a role in
activity
joke
requirement
meet
practise
association
continent
current
ensure
keep… under control
remove
rugby
polo
power boating
make way for
tae kwon do
previous
martial
martial art
supporter
branch
maintain
balance
judo
fencing
revise
involved
virtual
virtual reality
reality
proposal
extraordinary
character
interactive
set
tiredness
upon
feeling
happiness
headset
enable
3D
animation
monitor
pass on
fingertip
via
thousands of
sensor
be connected to
give out
opening
deliver
straw
world-famous
Brazilian
final
winning
sign
put forward
thrilled
besides
firefighter
burn
battle
whale
ant
fantastic
opportunity
industry
impress
impression
invest
exhibit
built-in
power-free
clay
study
soya bean
powder-free
announce
liquid
soap
powder
showcase
responsible
last but not least
programming
set up
employ
accuse
be accused of
piracy
sue
question
close down
bankrupt
file
popularity
criticize
fade
editor
therefore
voice
opinion
in my opinion
crash
PC
CPU
RAM
cursor
IT
nephew
come across
central
surface
southern
hero
science fiction
nameless
Victorian
gentle
journey
inexperienced
per
rescue
astrophysics
force
guide

This winter vacation,i have watched some British TV serials with my mother,and one of them is SHERLOCK.i really love this serial because SHERLOCK is always cool and smart and his friendship with John is so touching.I adore Sherkock most because i think he is so handsome and the way he plays the violin is so elegant.My mother,however,loves John because she thinks John is cute and warm.
After watching that serial,i began to want to be a dectative too.But maybe i am not clever enough.
Today i went shopping with my sister.We left our house at 7 am in the morning,and we took 211 bus to the shopping mall.My sister was so excited,but i was really boring during the shopping.When we had finished lunch,i thought we should go back home,but my sister insisted to stay.So we spent the afternoon there wandering.My sister triesd hundreds of closthes and i must waited in the shop.It is the longest day in my lfe.
We finally got back at 9 pm and we didnt buy anything.
There is a park near my home.Some nights after dinner,my dad and mum and i will go there for a walk.It is really beautiful,and sometimes we can see some ladies dancing in the park.Once i had a talk with them,and they told me they were very happy and they love dancing.After walking,we always feel good so i love walking too.
i went to a restaurant to have chinese hotpot tonight.It is very popular so we had book a seat one week ago.When we arrived,we found there were more than 50 people waiting for a seat.So it is wise to book that seat.
We enjoyed the meal very much and my father and me love the vegetables most.However,my mother loves the meat.All of us think highly of that restaurant and we decided that we would go there last month.
都是寒假的一些事情 你稍微改一下就更好了,加一些winter vacation进去

一个203 是一个轮回,99刚好轮33次,100就是第34次,也就是2

Today it's your duty to clean up the office.
这样的翻译不是更恰当么?我看楼上哪个句子感觉怪怪的.
而且肯定不要加for的!

又红又专,又香又甜,又快又稳,又香又脆

设某一家庭共有x人
A：90+45（x-1）=（45x+45）元；B：2/3×90x=60x元
若45x+45＜60x时,即当家庭人数大于3时,A旅行社收费较低；
若45x+45=60x时,即当家庭人数等于3时,A、B旅行社收费一样；
若45x+45＞60x时,即当家庭人数小于3时,B旅行社收费较低．

1 一棵树每年生长着一环
2.孩子和他们的家长是穷人
3.吃面包,稀饭
4.家长们都希望有晚宴,为穷人与他们的子女
5.他们希望他们的子女可以从晚餐中得到教育

我最后一次想你,最后一次想你.
因为明天,我将成为别人的新娘.
最后一次想你.

新学期到了,那么大家一定会有新的打算,我的打算又是什么呢?其实,我的打算和别人一样,就是要在新的学期里努力学习,认真听老师讲课,上课要积极发言.不仅如此,还要经常参加各类活动,做到这些,还远远不够,我还希望自己能在毕业考试上考出好成绩.我知道,要做到这些是很难很难的,但是只要你坚持到底,永不退缩,那这些又将变得非常容易.我想,人的希望是会随时改变的,不同的时间,不同的情况下,我们每个人的希望也是不同的.在新学期里,我的希望是永远记住母校,因为这毕竟是我生活了六年的小学啊!同时,我也希望能在这最后的半年里为我亲爱的母校做一点事情,留下一些美好的东西.我想,我一定会用实际行动来做这件事的.人在一生中,不管他成为了什么,是名人,或是伟人,还是极平凡的普通人,都会永远记住自己的母校,都对他有着非常深刻的感情,我也要做这样的人.我知道,每个人心里想的是不一样的,因为,人各有志,目标不同.如今我渐渐长大了,我的新目标不是做什么伟人,也不想当什么艺人,更不是成为科学巨人.而是长大后考上一座较好的大学,找到一份稳定的工作.在自己平凡的岗位上为国家,为社会作出不平凡的事,贡献出属于自己的一份力量,这就已经足够了.新学期里人人都有新打算,你一定也和我一样吧!让我们大家在新学期里携起手来,共同朝着自己的目标前进吧!

一,随机误差存在的原因
1在解释变量中忽略的因素的影响
2变量观测值观察误差的影响
3模型关系设定误差的影响
4其他随机因素的影响
二,古典线性回归模型的假定
1,E(U)=0 误差项期望为0
2,var（u）=sigma平方
3,不同误差项相互独立
4,解释变量与误差项不相关
5,误差项服从正态分布N(0,sigma平方)
三,t检验的零假设是系数为0,R平方是由回归方程解释的变差占总变差的百分比,因此0

下面是对于几种程度的割伤急救1轻微割伤,用清水洗净伤口,并用干净的布擦干既可.Below is for some degree of cut emergency 1 minor cuts,rinse the wound,and a clean cloth to wipe dry can.
2较重割伤,用肥皂水和清水洗净伤口,除去污染物并用干净的布或绷带包扎,3对血流不止的割伤,用干净的布或绷带直接包扎伤口并尽快把伤员送往最近的医院救护.2 heavier cut,with soapy water and rinse off with clean water,remove pollutants wound with a clean cloth or bandages,three more than the blood flow,cut with a clean cloth or bandage direct the wound as soon as possible and the wounded to the nearest hospital rescue.
我们平时活动要注意安全,注意保护自己 We usually activities should pay attention to safety,pay attention to protect themselves

微笑默叹.――《虞初新志·秋声诗自序》

I like watch movie very much.This is a story about the Lion King.Once there is a lion called Ziba whose father is a king.His parents are very kind to him. He has so many friends and very happy.
Unluckily, his father was killed one day. He lost the touch with his family since, then his good friend helped him.After many hardship, he beat his bad uncle and become the Lion King.iI think you will like that!

南康一带民风凶悍,认为县丞是个文人,都轻视他.
《吴履传》

标题,主题,时间,地点,人数,内容,组织者,具体安排,班主任签字

构造多项式序列f_k(x)=(2x)^k,k=0,1,2,...n
那么{f_k(x)}线性无关.
在[0,1]上不超过n次的多项式空间上定义内积：=[f(x)g(x)在[0,1]上的积分],
那么=2^{i+j}/(i+j+1)
于是A是{f_k(x)}的Gram矩阵的两倍,必然正定.

物质标准：
请注意可塑性物质必须小于0.06%
测试要求：
强度特性
测试：
在0度放置4个小时不断裂（仅限皮革）
最低要求：
过程中没有裂缝,碎屑或显著的变化.
测试方法：
ASTM D2136
太阳镜,雨伞,箱包的测试要求
所有适用的包装通过测试
邻苯二甲酸
邻苯二甲酸含量达标
DEHP,DBP,BBP,DINP,DIDP & DNOP (6P) 的物质总量为3%
虽然可能不太标准,但大概意思正确.很辛苦哦.

Dear teacher,
I am very glad to have the chance to write to you.
I'd like to tell you that I respect all our teachers and like all my classmates.
And,I want to learn from them and work hard together with them.
I dream to become a teacher in the future by working hard from now on.So I hope we can help one another.
With all the best!
Yours,
Li Hua

只能意译下：
So,the governor won't gain the people's respects and supports if he didn't care about and make profits for his people.Moreover,it is impossible that the people are willing to do anything or even to die to for the governor if he didn't care about and love his people.Without the people's usage and dead,it is useless if he only have the powerful army and the strong fort.Consequently,it is impossible if there is no enemy coming without the powerful army and the strong fort.
希望能够帮到你.

怎样巧学文言文?
一、 精解字词,储备足量的文言知识
逐字落实文言文课文中的每一个字的意义和用途,务必准确无误.因为只有积累了一定量的文言字词,才可能顺利地阅读文言文.
二、 巧记巧学.让文言文学习的轻松愉快
成语,是颇有生命力的古代词语的遗存,借助成语学习文言文,将古代和现代的词语沟通起来,使得文言文知识不那么枯燥,也不那么吓人,变得易记而浅显；还能够一石而二鸟,文言文和成语的学习同时经行.相得益彰.这是个轻便而俏皮的巧学方法.比如.【张】如果理解成语“账目结舌”中“张”是“睁开,睁大”意,就不难记住课文《童趣》中“张目结对日”中“张”的“睁开,睁大”意义.
字形,尤其古文字字形,比如甲骨文、金文、篆文,都隐藏着汉字的意义密码.探员其本字的古代写法,一眼就能洞察其意义,这样,即印象深刻有妙趣横生.这是个直观而形象的巧学方法.例如.【于】小篆字形（）像两手相与之形.由此可见“予”本义：授予.给予,给.
三、 归纳拓展,由“闻一”而“知十”
掌握了文言文的规律,就等于拿到了打开文言文知识的钥匙.文言文学习总是有章可循的,见到“陈胜者,阳城人也”,归纳为“者……也”判断句,进而归纳“乃、必、即、皆”等+谓语判断句；见到“吾谁与归”,归纳得出“疑问句中代词作宾语,宾语前置”的规律；见到“僵卧孤村不自哀”,归钠得出“否定句中代词作宾语,宾语前置”的规律；见到“何陋只有”“唯利是图”,归纳得出“之是褆宾”的规律；……
这样,在课本上学的是“一个”,而你收获的却是“一类”,学起文言文来就游刃有余了.
四、知识迁移,由课堂延伸到考场
把每一篇文言文课文都当成考场上的文言文阅读的材料,或设置题目作答,或比对已考过的的考题,即深入理解了课文,又从中培养语感,培养知识迁移能力和考场的应变能力.
例如,《送东阳马升序》第二段描写宋濂成人后求实
希望对你有帮助,望采纳!

I am a student body President, we will hold an English lecture.
Time: on October 7, 2006.
Location: the school the second dining room.
Speaker: professor at Peking University, American Mr. Johnson. Content: British English and American English differences.
Note 1: you can invite friends or classmates, but don't be late. After hearing the report, written in English composition.

跑、看、摸、瞪、读、走

雪花随风飘着,落在地上,树上,房顶上,虽然轻飘飘的但是来势凶猛,好象一群外星侵入者背着降落伞做着吞噬地球的美梦纷纷降落.

样品的质量m0=10.18Kg,体积V0=0.01m^3
样品的密度即河水的密度ρ=m0/V0=10.18Kg/0.01m^3=1018Kg/m^3
所以1m^3的河水（V总）的质量m总=ρV总=1018Kg/m^3×1m^3=1018Kg
河水可以看做是沙子和纯水的混合物,所以江水的总质量可以看做是沙子的质量+纯水的质量
m总=m沙+m水
河水的总体积可以看做是沙子的体积+纯水的体积
V总=V沙+V水
设每立方米的河水中含有的沙子的体积为V沙,则纯水体积为V总-V沙
m总=m沙+m水
m总=ρ沙V沙+ρ水V水
m总=ρ沙V沙+ρ水(V总-V沙)
1018=2500V沙+1000(1-V沙)
1018=2500V沙+1000-1000V沙
1500V沙=18
V沙=0.012m^3
m沙=ρ沙V沙=2500Kg/m^3×0.012m^3=30Kg

我有

刚步入初中,学习和生活方式都会有改变．学习也会很累,偏科也是很正常的．我也和你一样,步入初中时也有偏科情况．偏科情况可能源于小学时的成绩．,不要因为自己数学差而灰心,要善于找到自己的优点,你意识到自己数学差也就是一个优点,你发现了自己的缺点．就要去弥补．数学在初一要引起重视,每次做作业时要保证计算绝对不能错,这是最基本的一点．如果上课有什么不懂的问题,不要怕,可以去请教老师．如果有人嘲笑你,别去理会,他们看你越伤心,他们就越有劲．你不理会,他们就没戏了．还可以找一些适合自己的课外习题做,不会做的可以问老师．把每一种题性弄清楚,以后就不会错了．
同时建议你经常多做这方面的笔记,做好后经常要看,对于不懂的地方要经常问老师或同学,上课须认真听讲.学习态度要好等很多方面的因素.