20分钟之内,速速回答我用算数写,要简便. 1.小亮数学成绩为90分,以某一分为标准记作+15,如果小明数学成绩为70分

cosθ=a*b/|a||b|=-1/(√3√5)=-1/√15m*n=2k+4,k=-23/√6e^(sin(xy))*cos(xy)*(xdy+ydx)fx=yx^(y-1),fxy=x^(y-1)+yx^(y-1)lnx积分换序∫ye^(-y²)dy=1/2e^(-y²)=1/2(1-e^(-4))(1)不收敛2

它让我欣赏到百花盛开、春光如画的场景;
,他让我倾听到草长莺飞,夏虫低鸣的声音 ；
它让我品尝到山花烂漫,硕果累累的盛宴；
它让我感触到漫天飞雪,百里冰川的美景

18+(-12)+(-21)+(+12)
=18-12-21+12
=-3；
0.35+(-0.6)+0.25+(-5.4)
=（0.35+0.25）+(-0.6-5.4)
=0.6-6
=-5.4
-26 + 43 – 24 +13 – 46
=56-50-46
=-40;
49又25分之24 × （-5）
=(50-1/25)×(-5)
=-250+1/5
=-249.8;
（-32）÷4×（-8）
=-8×（-8）
=64；
（+22）× （-33） x （-4）x0
=0；
75÷（- 三分之二）x （- 二分之三）
=75×(-3/2)×(-3/2)
=75;
2x（-3）的平方 - 5除以二分之一x2


=2×9-5×2×2
=18-20
=-2

很容易,你可以随机抽取几组大豆,每组100粒,称出重量,再取100粒的平均值,再乘以100万就行.

1、First grade in the second floor.
2、In my grade of 600 students.
3、On the first floor has a toilet and four classes.
4、Our class has some beautiful girls.
5、My school is not reading room.
希望能帮助LL吧吧..

2008乘2007分之2006
=（2007＋1）×2006/2007
=2007×2006/2007＋1×2006/2007
=2006＋2006/2007
=2006又2006/2007

多读几遍

how soon will he come in twenty minutes

Music Appreciation【音乐欣赏】
What is your favorite kind of music?Do you like jazz,popular music,classical music,folk songs,blues,and so on?In high school I took one course called music appreciation which I greatly enjoyed.This was not to learn how to play a specific instrument but to learn how to read and listen to music as an art form.We read the stories about the lives of many composers and the history of the musical instruments themselves.Sometimes we listened to tapes at the language laboratory,or concerts.Music is sometimes called a universal language.A composer who cannot speak a single word of our language can make us feel joy and pride,exaltation and despair,peace and mystery through his music.
Singing Contributes to a Joyful Mind（歌唱带来欢乐）
Of all the things that make me happy,singing is what I like to do best.I sing for no particular purpose.In short,I sing for fun.There is no limit to what I sing,so long as it can let out my emotion and pass the pleasant voice to others.It is something more satisfactory and exciting to draw echoes from them.It is nothing bad to spread joy around,is it?As you can tell,singing is my second life.
在所有使我快乐的事中,唱歌是我最喜欢做的一件事.我唱歌不是为特别的目的.简言之,我为快乐万唱.我唱什么歌并无限制,只要它能发泄我的情绪,稚快乐的声音传给周遭的人就好了.能够引起他们的共鸣更是一件令人满意、兴奋的事.把欢乐散布四方不是件坏事,是吗?你可以看出,唱歌是我的第二生命.
还可以看看,作参考：

这应该是随机的,总之 不惊慌
无论是什么,你就当作 面试的是空气人,就行了,该怎样 就怎样讲

诗人张籍离开家乡,风尘仆仆的来到了洛阳城.
光阴似箭,转眼间中秋节都即将来临,树叶枯黄,都纷纷落了下来.洛阳城内,冷风阵阵,让人们感到这世间无比凄凉,张籍禁不住涌起思想之情,他怀念故土,怀念那些乡亲父老……
张籍想想亲自登门拜访亲朋好友们,顺便回到故乡去探望父母.可惜因为遇见一位正要回需要当官,没有办法.沮丧之季,恰巧遇见一位正要回到家乡的同乡,决心写一封家信委托同乡务必要把信转送到父母手中,以表孝心.信中有着甜蜜祝福语：祝父母“寿比南山,福如东海”,只怪对乡亲家人说的事情太多太多,万一这次是他与亲戚最后一次联系?如果这次的信没有将自己想表达的意思说清楚?那怎么办?此时此刻,张籍的内心是多么复杂,多么矛盾.
每当捎信的人刚要启程的时刻,他还要将信封拆开,唯恐写了一些不愉快的事情让父母为自己担忧,也担心会不会少写.有时候甚至不能发现错误他也迟迟不肯将信送走.虽然每次这样时,捎信人炯炯有神的目光都会显得黯然失色,但是他也了解张籍诗人顷刻的心情.
张籍就这样反反复复地用锐利的目光扫视这封信,他那紧锁的眉头正好照应了他没有思绪的心情,此时他是多么想回乡啊!
张籍望着蓝天多么想高歌呐喊,倾诉着自己的心愿……

等式的性质：两边同时加减乘除同一个数,两边的大小不变.
x÷2.7=7
x=7×2.7
x=18.9
22.2÷x=2
22.2=2x
x=22.2÷2
x=11.1
456-3x=123
456=123+3x
3x=456-123
3x=333
x=333÷3
x=111
x-12.3=4.56
x=4.56+12.3
x=16.86
5x=6.5
x=6.5÷5
x=1.3
10x+4x=1.12
14x=1.12
x=1.12÷14
x=0.08
1-3分之2x=5分之3
3分之1x=5分之3
x=5分之3÷3分之1
x=5分之9
4x-7×1.3=9.9
4x-9.1=9.9
4x=9.9+9.1
4x=19
x=19÷4
x=4.75

主张——倡议 、提倡

m

当夜晚悄悄来临时,四周一片寂静,
大自然也沉浸在梦乡.
明月依旧撒下它的光辉,
给周围的一切披上那一件又一件银装.