请讲一讲1.so many people were badly hurt __the traffic accident.

我只能说试着给你解释下.笨中的碳碳键是介于单双键之间的键（可认为一个单键一个双键那么组合成的六元环）,一般碳碳单键就是δ键,但像烯,就既含一个δ键又有一个π键,而苯不仅特殊在键,还有就是它当双键构成了共轭,所以是大π键.苯杂化：sp2杂化,每相邻两个C之间形成sp2-sp2 -C-C σ键,C和H间形成sp2-s C-H σ键,6个C中还有6个未成键的P轨道垂直形成个大π键

如果xx和xxx都是单数的话,只能用第一个,比如说：
A boy and a gird went to school.
如果xx是单数,xxx是复数的话,才能用第二个,比如说:
A boy and girls went to school.

我来

英语时态
英语共有16种时态,主要有：完成时态——现在完成时、过去完成时、将来完成时；进行时态——现在进行时、过去进行时、将来进行时、完成进行时；一般时态.
一般现在时
(1)一般现在时表示没有时限的持久存在的动作或状态或现阶段反复发生的动作或状态,常和副词 usually,often,always sometimes, regularly,near,occasionally,every year, every week 等连用.例如： The moon moves round the earth..
Mr. Smith travels to work by bus every day.
（2）在由after,until,before,once,when,even if,in case,as long as,as soon as,the moment 以及 if,unless 等引导的时间状语从句或条件状语从句中,通常用一般现在时代替将来时.例如： I will tell him the news as soon as I see him.
I will not go to countryside if it rains tomorrow.
I will have arrived by the time the meeting begins.
（3）某些表示起始的动词,可用一般现在时表示按规定、计划或安排要发生的动作,这类动词有：be,go,come,start,depart,arrive,begin,leave 等.例如：
The plane leaves at three sharp. The new teachers arrive tomorrow.
（4）在由why,what,where,whoever,who,that,as 等引导的从句中,也常用一般现在时代替将来时.例如：
Free tickets will be given to whoever comes first.
You’ll probably be in the same train as I am tomorrow.
一般过去时
（1）表示过去某一特定时间所发生的、可完成的动作或状态,常与表示确切过去时间的词、短语或从句连用.如 yesterday, last year, in 1949, a minute ago, just now
例如： We went to the pictures last night and saw a very interesting film.
（2）表示过去习惯性动作.例如：
He always went to class last.
I used to do my homework in the library.
（注意与be used to doing短语的区别）
（3) 在since 引导的状语从句多用一般过去时.主句中一般用完成时
He has changed much since I saw him last.
一般将来时
（1）表示将来打算进行或期待发生的动作或状态.例如：
I shall graduate next year.
（2）几种替代形式：
1）be going to +v在口语中广泛使用,表示准备做或将发生的事情.例如：
I’m going to buy a house when we’ve saved enough money.
2）be to +v表示计划安排要做的事,具有“必要”的强制性意义.例如：
I am to play tennis this afternoon.
3）be about to +v表示即将发生的事情.例如： He was about to start.
4）be due to +v表示预先确定了的事, 必定发生的事.例如：
The train is due to depart in ten minutes.
5）be on the point/verge of +v – ing 强调即将发生的某种事态.例如：
The baby was on the point of crying when her mother finally came home.
6) 有些动词用现在进行时,表示在最近按计划或安排要进行的动作,多和表示未来时间的状语连用 We are leaving on Friday.
现在进行时
（1）表示现在正在进行的动作,常与now,right now,at the moment,for the time being,for the present等连用.例如：
Don’t disturb her. She is reading a newspaper now.
（2）表示现阶段经常发生的动作, 常与always,continually,forever,constantly等连用.例如： My father is forever criticizing me.
（3）表示根据计划或安排在最近要进行的事情.具有这种语法功能的动词仅限于过渡性动词.即表示从一个状态或位置转移到另一个状态或位置上去的动词.常用的有：go,come,leave,start,arrive,return等.例如：
They are leaving for Hong Kong next month.
（4）有些动词不能用进行时,这是一类表示“感觉,感情,存在,从属”等的动词.如：see,hear,smell,taste,feel,notice,look,appear,（表示感觉的词）；hate,love,fear,like,want,wish,prefer,refuse,forgive（表示感情的动词）；be,exist,remain,stay,obtain（表示存在状态的动词）；have,possess,own,contain,belong,consist of,form（表示占有与从属的动词）；understand,know,believe,doubt,forget,remember（表示思考理解的动词）.但是如果它们词义改变,便也可用进行时态.例如： Tom looks pale. What’s wrong with him?
（look 在此为联系动词,意为“显得,看上去”）
Tom is looking for his books. （look 在此为实义动词,意为“寻找”）
过去进行时
过去进行时表示一个过去的动作发生时或发生后,另一个过去的动作正在进行,或表示过去反复的习惯,常与always,continually,constantly等动词连用.例如：
We were discussing the matter when the headmaster entered.
Whenever I visited him, he was always writing at the desk.
将来进行时
将来进行时主要表示将来某一时刻正在进行的动作,或表示要在将来某一时刻开始,并继续下去的动作.常用来表示礼貌的询问、请求等.例如：
This time next day they will be sitting in the cinema.
What will you be doing at six tomorrow evening?
完成进行时
（现在、过去、将来）完成进行时是（现在、过去、将来）完成时的强调形式,将放在完成时态部分讲述.
现在完成时
（1）现在完成时用来表示对目前状况仍有影响的,刚刚完成的动作（常与yet,already,just连用）,或者过去某一时刻发生的,持续到现在的情况（常与for,since连用）.例如：
I have just finished my homework. Mary has been ill for three days.
（2）常与现在完成时连用的时间状语有：since, for, during, over等引导出的短语；副词already, yet, just, ever, now, before, often, lately, recently等；状语词组this week (morning, month, year), so far, up to now, many times, up to the present等.例如：
I haven’t been there for five years.
So far, she hasn’t enjoyed the summer vacation.
There have been a lot of changes since 1978.
（3）完成时态可用在下列结构中：
This (That) is (was) the first (second…) time +定语从句；This (That, It) is (was) the only (last) + n +定语从句；This (That, It) is (was) +形容词最高级+ n +定语从句.如果主句的谓语动词是一般现在时,从句的谓语动词通常用现在完成时；如果主句谓语动词是一般过去时,从句谓语动词通常用过去完成时.例如：
This is one of the rarest questions that have ever been raised at such a meeting.
There was a knock at the door. That was the second time someone had interrupted me that evening.
过去完成时
（1）表示过去某时间前已经发生的动作或情况,这个过去的时间可以用by,before等介词短语或一个时间状语从句来表示；或者表示一个动作在另一个过去动作之前已经完成.例如：
We had just had our breakfast when Tom came in.
By the end of last year they had turned out 5, 000 bicycles.
（2）动词expect, hope, mean, intend, plan, suppose, wish, want, desire等用过去完成时,表示过去的希望、预期、意图或愿望等没有实现.例如：
I had meant to take a good holiday this year, but I wasn’t able to get away.
另外两种表示“过去想做而未做的事”的表达方式是：
1）was / were + to have done sth, 例如：
We were to have come yesterday, but we couldn’t.
2）intended (expected, hope, meant, planned, supposed, wished, wanted, desired) + to have done sth, 例如：
I meant to have told you about it, but I forgot to do so.
（3）过去完成时常用于以下固定句型：
1）hardly, scarcely, barely + 过去完成时+ when + 过去时.例如：
Hardly had I got on the bus when it started to move.
2）no sooner +过去完成时+ than +过去时.例如：
No sooner had I gone out than he came to see me.
3）by (the end of ) +过去时间,主句中谓语动词用过去完成时.例如：
The experiment had been finished by 4 o’clock yesterday afternoon.
将来完成时
将来完成时表示在将来某一时刻将完成或在另一个未来的动作发生之前已经完成的动作；也可以用来表示一种猜测.常与将来完成时连用的时间状语有：by (the time / the end of ) + 表示将来时间的短语和句子；before (the end of ) + 表示将来时间的词语或句子；when, after等加上表示将来动作的句子等.例如：
By this time tomorrow you will have arrived in Shanghai.
I shall have finished this composition before 9 o’clock.
When we get on the railway station, the train will probably have left.
完成进行时
完成进行时是完成时的强调形式,有现在完成进行时,过去完成进行时,将来完成进行时.
（1）现在完成进行时表示过去某一时刻之前开始的动作或状态一直延续到过去某一时刻.例如：
I have been looking for my lost b here?
但就大多数动词而言,在不用表示一段时间地状语的情况下,现在完成时表示动作的完成,而现在完成进行时表示动作的继续. ook for three days, but I still haven’t found it.
有少数动词如work, study, live, teach 等, 用现在完成时和现在完成进行时意思相差无几.
How long have you studied here?
How long have you been studying
They have widened the road.
They have been widening the road.
（2）过去完成进行时表示过去某一时刻之前开始的动作或状态一直延续到过去某一时刻.例如：
It had been raining cats and dogs for over a week and the downpour had caused landslides in many places.
（3）将来完成进行时表示在将来某一时刻之前开始的一个动作或状态一直延续到将来某一时刻.例如：
By the time you arrive tonight, she will have been typing for hours.

prefer最常见的意思是"宁可"、"宁愿(选择)"、"比较喜欢"、"更喜欢"等,可以构成以下结构.
一.prefer sth.
"Do you like French?""Yes,but I prefer English.""你喜欢法语吗?""喜欢,但是我更喜欢英语."
注:prefer是"比较喜欢,更喜欢"的意思,即like better,因此就不能再与better,more等比较级词语连用.
二.prefer over sth.
I prefer over this newly-built lab,and you?我比较喜欢这个新建的实验室,你呢?
They prefer over new works that sing of their life today.他们更喜欢歌颂他们今天生活的新作品.
三.prefer sth.above all others
I prefer the book above all others.我最喜欢这本书.
四.prefer A to B
I prefer the original book to the revised edition.我觉得原书比修订本好.
五.prefer doing A to doing B
Even on holidays Mr.Wang preferred reading to doing nothing.即使在假日,王先生宁愿读书而不愿闲着.
注:在这种结构中,to为介词,而不是不定式符号,故其后应当接动名词形式,决不能接动词原形.另外,为了保持前后对应关系,prefer后面也应当接动名词形式.
六.prefer to do sth.
They prefer to spend the rest of the morning wandering in the streets.他们比较喜欢把早上剩下的时间都用来在街上闲逛.
七.prefer doing sth.
So you prefer speaking without referring to your notes?这么说,你更喜欢不看稿子做报告了?
注:这种prefer后面接动名词的结构,用来谈论一般情况下"更喜欢某种活动",而在一个特定场合下表示"特别喜欢"时,得用上述prefer后接动词不定式结构.
八.prefer to do sth.rather than do sth.
These workers prefered to work extra hours at night rather than leave the work until the next week.这些工人宁愿加班干,也不愿把工作留到下一个星期.
注:这种结构中的rather than可以置于句首.例如:
Rather than go on holiday to the seaside I prefer to work days and go to school nights.我宁愿白天工作,晚上上学,而不愿到海边度假.
注:有时rather可以移至第一个不定式之前,而让than留在第二个不定式之前,即为prefer rather...than结构.这种用法多见于书面语言,在口语中很少用.
九.prefer to do sth.rather than doing sth.
They prefer to join in the celebrations rather than going on a visit to the Palace Museum.他们宁愿参加庆祝活动而不愿参观故宫.
注:有时名词也可用于rather than之后,这种用法多用以表示在某种具体场合的选择.
十.prefer sb.to do sth.
I prefer you to spare some time to come to our art exhibition next week.我宁愿你们下星期抽出点时间来看看我们的美展.
十一.prefer+that-clause.在that宾语从句中,我们应当用虚拟语气"should+动词原形",其中的should可以省略.
We prefer that each new student take a science course.我们希望每位新生修一门理科课程.
十二.prefer sth.(or sb.)+adj.
I prefer the door open.我宁愿门开着.
I prefer my coffee black.我爱喝不加奶的咖啡
还有以下注意：
1、后接不定式时与rather than 或instead of连用,如：He prefered to die rather than (to) steal./ He perfered to die instead of stealing.他宁死也不去偷窃.
2、注意介词搭配,如：I prefer swimming to skating.(I like swimming better than skating.)我喜欢游泳胜过滑冰.prefer 因其本身含有比较之意,而不可再与more 或most连用.
3、prefer＋名词或动名词“宁愿”,“更喜欢”.He comes from Shanghai,so he prefers rice.他是上海人,因此更喜欢吃米饭.I prefer going by bike.我宁愿骑单车去.I prefer the white one.我喜欢那个白的.
4、prefer to do “愿意做”.I prefer to go at once.我愿意马上就走.
5、prefer sb.to do “愿意某人做” I prefer you to go at once.我倒希望你马上就走.
6、prefer to sth.“宁愿做...而不做...”.I prefer tea to milk.我宁愿喝茶也不喝牛奶.I prefer watching TV to going out.我宁愿看电视也不出去.
7、prefer to do sth.rather than do sth.“宁愿做...而不做...” I prefer to watch TV rather than go out.我宁愿呆在家里也不出去.
8、prefer＋ that从句“宁愿”（从句一般用虚拟语气）I prefer that you should do it.我宁愿你做这件事.
这些是prefer的用法,你认真看,对你有很大帮忙的~

不是大师,翻译一下请大师指教.
pancake flavored with suger and green onion

oth [简明英汉词典]
[bEJW]
adj.两者,双方的
pron.双方,两者
each [简明英汉词典]
[i:tF]
adj.各自的,每个的,每一
pron.各,各自,每个
adv.每个
either [简明英汉词典]
[5aITE(r)]
adj.任一的,(两方中的)每一方的
pron.任一,随便任一个
conj.或者,也
neither [简明英汉词典]
[5naiTE,5ni:TE]
adj.pron.两者都不
conj.既不...又不,也不

he is taller than (me) 这样的句式一般都要跟人称的宾语格式,约定俗成的^_^,语言这东西,很多都是没有特别的理由的,说的人多了就成王道了.

What is sucess?Wealth?Prestige?or absolutely right?I think all of you have your own ideas,now let's welcome ** to give us his definition of sucess
供参考

1.（1036-1000）/1000*100%=3.6%
2.150*5%=7.5万元

480 / 80 = 6分钟
则剩下还有22-6 = 16分钟原计划路程
所以这段距离有16/6*480 = 1280M

x/4+x=15
5x/4=15
x=12

特殊疑问词+ever是无论...
however, whenever, wherever,是疑问副词,引导让步状语从句.
whoever, whomever,whatever,是疑问代词,引导让步状语从句或名词性从句.
1.However hard he try, he can't succeed.
2.Whenever I see him, he always smiles to me.
3.Whereever you go, don't forget your hometown.
4.Whoever does wrong should be punished.
5.I will give the prize to whomever you recommand.
6.I will buy you whatever you want.

one of which (= 其中之一) 可以引导定语从句,而 one of them (= 其中一个) 不行,如：
I have five books,one of which is English.(=我有五本书,其中有一本是英语书.) ；
I have five books ,and one of them is English.(意思同上)；
one of which 只能指“物”；而 one of them 既能指“物”,也能指“人”,如：
There are five children in the room,and one of them is reading.(= 房间有五个孩子,其中一个在看书).

第一题,由回答no知道肯定不是c.此外,如果是d.那么lost后面必须加宾语,再者,由句意知,我是被打败了,因而是A
第二题由空后面的BY知道,instead肯定不行,因为两个介词不可连用,而且,instead一般与of连用,而且,这个题目由句意知,考的是被动语态,而且,情态动词后面加的是动词原型,因而,只能选D
第三题考的还是被动语态,但是存在某些动词,它后面必须加介词的,比如Do you want a pen to writd with 这个就是要加介词的例子,因而选b
第四个是关于连词的选择,a是首先,b是最后,c是第一个,d的话,应该是错误用法,排除后选a
这些都是我用手机打出来的,可以的话,给我附加点财富值吧,现在很缺

1) 陈述部分的主语是I,疑问部分要用 aren't I.
I'm as tall as your sister,aren't I?
2) 陈述部分的谓语是wish,疑问部分要用may +主语.
I wish to have a word with you, may I?
3) 陈述部分用 no, nothing, nobody, never, few, seldom, hardly, rarely, little等否定含义的词时,疑问部分用肯定含义.
The Swede made no answer, did he / she?
Some plants never blown (开花), do they ?
4) 含有ought to 的反意疑问句,陈述部分是肯定的,疑问部分用shouldn't / oughtn't +主语.
He ought to know what to do, oughtn't he? / shouldn't he?
5) 陈述部分有have to +v. (had to + v.),疑问部分常用don't +主语（didn't +主语）.
We have to get there at eight tomorrow, don't we?
6) 陈述部分的谓语是used to 时,疑问部分用didn't +主语或 usedn't +主语.
He used to take pictures there, didn't he? / usedn't he?
7) 陈述部分有had better + v. 疑问句部分用hadn't you?
You'd better read it by yourself, hadn't you?
8) 陈述部分有would rather +v.,疑问部分多用 wouldn't +主语.
He would rather read it ten times than recite it, wouldn't he?
9) 陈述部分有You'd like to +v. 疑问部分用wouldn't +主语.
You'd like to go with me, wouldn't you?
10) 陈述部分有must 的疑问句,疑问部分根据实际情况而定.
He must be a doctor, isn't he?
You must have studied English for three years, haven't you? / didn't you?
He must have finished it yesterday, didn't he?
11) 感叹句中,疑问部分用be +主语.
What colours, aren't they?
What a smell, isn't it?
12) 陈述部分由neither… nor, either… or 连接的并列主语时,疑问部分根据其实际逻辑意义而定.
Neither you nor I am engineer, are we?
13) 陈述部分主语是指示代词或不定代词everything, that, nothing, this, 疑问部分主语用it.
Everything is ready, isn't it?
14) 陈述部分为主语从句或并列复合句,疑问部分有三种情况：
a. 并列复合句疑问部分,谓语动词根据邻近从句的谓语而定.
Mr. Smith had been to Beijing for several times, he should have been in China now, shouldn't he?
b. 带有定语从句,宾语从句的主从复合句,疑问部分谓语根据主句的谓语而定：
He is not the man who gave us a talk, is he?
He said he wanted to visit Japan, didn't he?
c. 上述部分主句谓语是think, believe, expect, suppose, imagine等引导的定语从句,疑问部分与宾语从句相对应构成反意疑问句.
I don't think he is bright, is he?
We believe she can do it better, can't she?
15) 陈述部分主语是不定代词everybody, anyone, somebody, nobody, no one等,疑问部分常用复数they,有时也用单数he.
Everyone knows the answer, don't they? (does he?)
Nobody knows about it, do they? (does he?)
16) 带情态动词dare或need的反意疑问句,疑问部分常用 need (dare ) +主语.
We need not do it again, need we ?
He dare not say so, dare you?
当dare, need 为实义动词时,疑问部分用助动词do + 主语.
She doesn't dare to go home alone, does she?
17) 省去主语的祈使句的反意疑问句,疑问部分用will you.
Don't do that again, will you?
Go with me, will you / won't you ?
注意： Let's 开头的祈使句,后用shall we?
Let us 开头的祈使句,后用will you?
Let's go and listen to the music, shall we?
Let us wait for you in the reading-room, will you ?
18) 陈述部分是"there be"结构的,疑问部分用there省略主语代词.
There is something wrong with your watch, isn't there?
There will not be any trouble, will there?
19) 否定前缀不能视为否定词,其反意疑问句仍用否定形式.
It is impossible, isn't it?
He is not unkind to his classmates, is he?
20) must在表"推测"时,根据其推测的情况来确定反意疑问句.
He must be there now, isn't he?
It must be going to rain tomorrow, won't it?
快速记忆表
陈述部分的谓语 疑问部分
I aren't I
Wish may +主语
no,nothing,nobody,never,
few, seldom, hardly, 肯定含义
rarely, little等否定
含义的词
ought to（肯定的） shouldn't/ oughtn't +主语
have to+v.(had to+v.) don't +主语(didn't +主语)
used to didn't +主语或 usedn't +主语
had better + v. hadn't you
would rather + v. wouldn't +主语
you'd like to + v. wouldn't +主语
must 根据实际情况而定
感叹句中 be +主语
Neither…nor,
either…or 连接的根 据其实际逻辑意义而定
并列主语
指示代词或不定代词
everything,that, 主语用it
nothing,this
并列复合句 谓语根据邻近从句的谓语而定
定语从句,宾语从句的
主从复合句 根据主句的谓语而定
think,believe,expect,
suppose,imagine等引导 与宾语从句相对应的从句
everybody,anyone,
somebody,nobody,no one 复数they, 单数he
情态动词dare或need need (dare ) +主语
dare, need 为实义动词 do +主语
省去主语的祈使句 will you?
Let's 开头的祈使句 Shall we?
Let us 开头的祈使句 Will you?
there be 相应的谓语动词+there(省略主语代词）
否定前缀不能视为否定词 仍用否定形式
must表"推测" 根据其推测的情况来确定反意疑问句

我改为从句你就可以看出来了.
Because the food tasted good,the food was soon sold out
看出没用被动是吧?taste 是连系动词,和look,sound feel smell 一样不能用于被动语态
由于表主动,所以用表主动的tasting 现在分词短语做原因状语,而不能用表被动的Tasted,Being tasted
请在客户端右上角评价点“满意”即可,

I agree that----.这个that引导的就是宾从,
I don't know how to----wh-引导的也是宾从.
This is my brother who---
a cake that/which----就是定从,多修饰名词.
The fact is that---就是表从.

天网恢恢：天的禁网广大而宽疏.恢恢：意思为广大而宽疏.
语出《老子》七十三章.意思是天道公平,作恶就要受惩罚,它看起来似乎并不周密,但最终不会放过一个坏人.
〔例〕老老虎第二次造谣时得意忘形,过高地估计了自己,低估了人民群众辨别是非的能力,肆意胡言,终于被群众识破其鬼域伎俩,身败名裂.,诚不我欺也.

1．甲乙两个水管单独开，注满一池水，分别需要20小时，16小时.丙水管单独开，排一池水要10小时，若水池没水，同时打开甲乙两水管，5小时后，再打开排水管丙，问水池注满还是要多少小时？

1/20+1/16＝9/80表示甲乙的工作效率
9/80×5＝45/80表示5小时后进水量
1-45/80＝35/80表示还要的进水量
35/80÷（9/80-1/...

不是碳氧双键被氧化!碳氧双键被氧化就好像氧化二氧化碳一样不合逻辑,实际上是氧化剂将醛基的氢拿下来之后羟基接上去形成酸

Zn的金属性活泼远远强于Cu,因此Zn易失去电子,而Cu2+又很容易得到电子.
在原电池体系下,负极(失去电子的一方）的Zn失去电子变成Zn2+,失去的电子经导线到达正极（得电子的一方）给了Cu2+,于是Cu2+得到电子被还原成Cu单质.
图中导线和KCl桥盐是为了使其形成闭合回路,保证体系电荷守恒.
正极的铜棒只是用做导体,负极的ZnSO4做电解液,均不参加反应.
反应实质是： Zn + Cu2+ = Zn2+ + Cu
类似的原电池中铜和硫酸铜、镁和硫酸镁也可以反应,
反应实质是： Mg + Cu2+ = Mg2+ + Cu（其中Cu做导体,MgSO4做电解液,均不参加反应）
现在能明白了吗,如果还有不清楚的地方希望继续提出

就是电势相同的地方,导线可以捏合成1个点

分子晶体中的键是共价键,因两个原子共用电子对而产生,共用电子对受到两个原子核的共同吸引使两个原子形成化合物
分子间的作用力是分子与分子间的力,是把分子聚集在一起的作用力,又叫范德华力,只有在分子与分子充分接触时,才有明显的作用,气态时,就不再考虑分子间力的存在

精度值是指刻度尺的最小刻度所代表的值（最小分度值）例如最小刻度是毫米的刻度尺,其精度值就是1毫米,而读数时可读到毫米的下一位,毫米的下一位数就是估计值.注意估计值只有一位,即测量值的最后一位.

在会议上发言

平常睡眠不注意引起的,真空抽脂祛眼袋手术实际上是利用电凝器的特殊电刀或激光在眼睛的结膜(下眼皮内)作一个小口子,从中将眼眶中的脂肪去除,消除了眼袋,而外表眼皮却无伤疤,确切地说应该是无疤祛眼袋.

圆的半径是1.5cm 周长是2*1.5*3.14=9.42

维就是向量组中线性无关的向量个数
用几何来说
比如,有1条线,就是1维
又有1条不和这个线平行的线,就是2维

绳子剪断后,水面会下降.
所以水的重力势能减小,即：机械能减小.

由图丙可知：赖氨酸的密码子为AAA/AAG,若突变为异亮氨酸则只需一个碱基突变即可,即AAA->AUA,同理可知,除了丝氨酸AAA/AAG->AGU/AGC需要后面两个碱基同时发生突变（即答案中的“需同时替换两个碱基”）之外,其他的氨基酸都只需要一个碱基突变即可,而且两个个碱基同时发生突变的可能性远远小于一个碱基突变的可能性,所以突变为丝氨酸的可能性最小.

看元素周期表啊,在看元素组成的符号,查元素表就行啦.(背过符号很重要的).且做题的时候便越老越了解.

风——即空气流动形成风,像水流一样,空气先经过的地方就是上风处.就像上下游.

75

爱因斯坦跟我说,E=MC2.速度越快,质量越大,导致其不能循环加速.

如图外面的等势面类似鸡蛋壳,
再往里面的等势面类似花生壳,
再往里面的等势面是两相接触的偏长的球面,
再往里面的等势面是不标准的一系列同心球面.

yuanshi=sin40°*(√3*cos10°-sin10°)/cos10°
=sin40°*(-2cos40°)/cos10°
=-1
ni shi bu shi JCW

3600″=60′=1°
1度=π/180弧度 1弧度=180/π度 (180°=1π)

反义疑问句是在陈述句（肯定形式或否定形式）后加一个简短问句,对陈述句所叙述的内容提出相反的疑问.通常反义疑问句是提出情况或看法,问对方同不同意.
1、构成：陈述句+反义疑问.陈述句和疑问句的主语以及谓语动词在人称、数、时态上通常要保持一致.
反义疑问句的主要形式有两种：
（1）肯定陈述句+否定反义疑问句.例如：
The songs in the movie "The Sound of Music" are really beautiful,aren't they?
电影《音乐之声》中的歌曲很美,不是吗?
（2）否定陈述句+肯定反义疑问句.例如：
You haven't finished your homework yet,have you?
你没有做完家庭作业,是吗?
2、反义疑问句的回答：答语要和实际情况相符合,遵循“实事求是”的原则.肯定的答案用yes+肯定结构,否定的答案用no+否定结构.例如；
A:You aren't a teacher,are you?你不是老师,是吗?
B:Yes,i am./ No,i'm not.不,我是./ 是的,我不是.
3、几种特殊情况；
1) 陈述部分的主语是I,疑问部分要用 aren't I.
I'm as tall as your sister,aren't
2) 陈述部分的谓语是wish,疑问部分要用may +主语.
I wish to have a word with you,may
3) 陈述部分用 no,nothing,nobody,never,few,seldom,hardly,rarely,little等否定含义的词时,疑问部分用肯定含义.
The Swede made no answer,did he / she?
Some plants never blown (开花),do they
4) 含有ought to 的反意疑问句,陈述部分是肯定的,疑问部分用shouldn't / oughtn't +主语.
He ought to know what to do,oughtn't he?/ shouldn't he?
5) 陈述部分有have to +v.(had to + v.),疑问部分常用don't +主语（didn't +主语）.
We have to get there at eight tomorrow,don't we?
6) 陈述部分的谓语是used to 时,疑问部分用didn't +主语或 usedn't +主语.
He used to take pictures there,didn't he?/ usedn't he?
7) 陈述部分有had better + v.疑问句部分用hadn't you?
You'd better read it by yourself,hadn't you?
8) 陈述部分有would rather +v.,疑问部分多用 wouldn't +主语.
He would rather read it ten times than recite it,wouldn't he?
9) 陈述部分有You'd like to +v.疑问部分用wouldn't +主语.
You'd like to go with me,wouldn't you?
10) 陈述部分有must 的疑问句,疑问部分根据实际情况而定.
He must be a doctor,isn't he?
You must have studied English for three years,haven't you?/ didn't you?
He must have finished it yesterday,didn't he?
11) 感叹句中,疑问部分用be +主语.
What colours,aren't they?
What a smell,isn't it?
12) 陈述部分由neither… nor,either… or 连接的并列主语时,疑问部分根据其实际逻辑意义而定.
Neither you nor I am engineer,are we?
13) 陈述部分主语是指示代词或不定代词everything,that,nothing,this,疑问部分主语用it.
Everything is ready,isn't it?
14) 陈述部分为主语从句或并列复合句,疑问部分有三种情况：
a.并列复合句疑问部分,谓语动词根据邻近从句的谓语而定.
Mr.Smith had been to Beijing for several times,he should have been in China now,shouldn't he?
b.带有定语从句,宾语从句的主从复合句,疑问部分谓语根据主句的谓语而定：
He is not the man who gave us a talk,is he?
He said he wanted to visit Japan,didn't he?
c.上述部分主句谓语是think,believe,expect,suppose,imagine等引导的定语从句,疑问部分与宾语从句相对应构成反意疑问句.
I don't think he is bright,is he?
We believe she can do it better,can't she?
15) 陈述部分主语是不定代词everybody,anyone,somebody,nobody,no one等,疑问部分常用复数they,有时也用单数he.
Everyone knows the answer,don't they?(does he?)
Nobody knows about it,do they?(does he?)
16) 带情态动词dare或need的反意疑问句,疑问部分常用 need (dare ) +主语.
We need not do it again,need we
He dare not say so,dare you?
当dare,need 为实义动词时,疑问部分用助动词do + 主语.
She doesn't dare to go home alone,does she?
17) 省去主语的祈使句的反意疑问句,疑问部分用will you.
Don't do that again,will you?
Go with me,will you / won't you
注意：Let's 开头的祈使句,后用shall we?
Let us 开头的祈使句,后用will you?
Let's go and listen to the music,shall we?
Let us wait for you in the reading-room,will you
18) 陈述部分是"there be"结构的,疑问部分用there省略主语代词.
There is something wrong with your watch,isn't there?
There will not be any trouble,will there?
19) 否定前缀不能视为否定词,其反意疑问句仍用否定形式.
It is impossible,isn't it?
He is not unkind to his classmates,is he?
20) must在表"推测"时,根据其推测的情况来确定反意疑问句.
He must be there now,isn't he?
It must be going to rain tomorrow,won't it?

NaHCO3,是白色晶体,又名小苏打,热稳定性没有苏打(NA2CO3)稳定,与酸反应,与碱也反应,不与硫酸镁,氯化钡反应

就是从一个面去看这个物体时,所看到的图形
比如数学中的立体几何证明,很多题都要用到投影的方法.
物理中：不可伸长的杆或绳绕一点转动时,尽管各点速度不同,但各点速度沿绳方向的投影相同.
所谓不可伸长就可以是说刚体了,因为不可伸长,所以不可能在杆方向上有杆上A点的速度与杆上B点的速度不同（要va1与vb1都沿杆）,因为如果不同就是会产生增加的位移也就是说杆或者绳子被拉长了,就与不可伸长不符合.而这个定理就是以这个为依据和核心的,但是要知道a与b点的速度不一定都沿杆,但根据矢量的（正交）分解,va和vb都分别可以分解va1沿杆va2垂直与杆.但是沿杆方向上速度一定相同,即va1=vb1所以这个定理可以运用来列方程等式.

通普的标准方法这样叙述：称取规定量的于105~110℃烘
干至恒重的基准邻苯二甲酸氢钾,…… .
请注意“恒重”两字.意思是说：温度升到规定温度范围并保持
一段时间后,把被烘物冷却到室温(当然是放在干燥器中)称量.
并再一次烘一段时间,再冷却称量.如果两次的质量之差可
以忽略不计,则认为已经“恒重”.可以用于称量几份基准
物供测定用了.
一般为了省时间和省步骤,只烘一次比较长的时间,如半小时
以上.这是参考意见,请根据实际测定现场情况而定.

你说的正确 what后面“什么时候用单数,什么时候用复数”根据动词后面的名词的单复数来定 是不是从句做主语 主句谓语动词皆单数啊?答：一般情况

-1/2+-1/6+-1/10+-1/12+-1/20+-1/30+-1/42+-1/56+-1/72+-1/90=-1
应该是对的,我数学还挺好的.

管仲和鲍叔牙.他俩是很好的朋友,年轻时鲍叔牙帮助家里贫穷的管仲,成为知己,管仲曾说：生我者父母,知我者鲍叔也.后来鲍叔牙推举管仲为宰相,管仲也回报了鲍叔牙,时间的人都称赞鲍叔牙的人品和二人之间的友谊.

直线与圆相切,则圆心到直线的距离等于圆的半径

比如“你吃饭”,这里的“你”是主语,“吃”是谓语,“饭”就是宾语；
“我是学生”,这里的“我”是主语,“是”是谓语,“学生”就是宾语.
谓语一般只是个单词,如果是个句子就是谓语从句.
do/does/did就是助动词
感官动词“看起来look、闻起来smell,尝起来taste”、持续动词“keep,rests”等都是系动词
其实你可以看些趣味语法的书,英语是个细功夫活,首先得培养兴趣,学习的时候要学会总结,如果只是要应付考试还是不难的,加油!

同一个碳上连接多个羟基也不稳定,判断的话没有简单的方法,靠积累就行了

一个数的负三次方就是这个数的三次方的倒数
比防说2的负三次方就是8分之一
64/125的负三次方等于1953125/262144