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1,英语中isare dodoes分别什么时候用

IS 、ARE 是没有动词的时候用,原型是助动词BE,IS用于单数,ARE用于复数;DO和DOES是有动词的时候用,DOES用于单数第三人称,其他用DO.

英语中isare dodoes分别什么时候用

2,排列组合问题里什么时候会用到隔板法请举例说明

隔板法要求是把没有区别的几个“球”分成有序的几堆。 由于“球”没区别,所以各堆之间只能体现数目,无法体现是哪个球。其方法有二。 1、不允许有空堆。 例:x+y+z=10的正整数解。 9个空中放两个板成为三份。 2、允许有空堆。 例:x+y+z=10的非负整数解。 10个“球”和两个板占的12个位置中找两个 位置放板即可。你的问题中,先去掉1+2+3=6个球,就是说,先在三个盒子里各放上要求的最少球数,所以另外要放的球的数为x,y,z,则x+y+z=14,求它的非负整数解的个数,用第2类方法。
因为书是相同的,所以可以让1,2,3阅览室分别放1,2,3本书,在将剩下的4本书进行分配,决定分配方案的种数,在将4本书分给一个阅览室,则有3种分法。如果将4本书分给二个阅览室,那么就有9种分法,如果将4本书分给三个阅览室,则有3种分法。所以:3+9+9=15
应用隔板法必须满足三个条件: (1) 这n个元素必须互不相异 (2) 所分成的每一组至少分得一个元素 (3) 分成的组别彼此相异 组合不排列的情况可以用隔板法

排列组合问题里什么时候会用到隔板法请举例说明

3,什么时候用much什么时候用many在句子中

1、many + 可数名词,much + 不可数名词How many people are there at the meeting?How much time has we left?2、many 修饰或代替可数名词(复数),与 few(少数)相对;而 much 用来修饰或代替不可数名词(单数),与little(少量)相对。3、 两者都可与 more 连用,其区别仍然是 many more之后接复数名词,much more 之后接不可数名词。4、另外,其后修饰的不是名词,而是形容词或副词,则用much more,不用many more。扩展资料How many 和 How much 的区别与用法:一、区别1、how many用来修饰可数名词的复数,它的句式是:How many+复数名词+ 一般疑问句+2、how much用来修饰不可数名词,表示数量,也可单独使用。二、how many的用法1、对there be句型中主语的数量如:some, five, only one等提问时,如果主语是可数名词,不管主语是单数还是复数一般都用复数形式提问。因为问话人不知道具体的数量是多少,而且many只能接可数名词复数形式,所以be一定要用are.即用How many+可数名词复数+are there+地点/时间状语 的句型结构。There is a book on the desk. (用how many改为特殊疑问句)How many books are there on the desk There are seven days in a week. (对划线部分进行提问)How many days are there in a week 三、how much 的用法1、用来询问事物的数量,后接不可数名词。How much milk is there in the glass 玻璃杯里有多少牛奶? 2、用来询问事物的重量。例如: -How much does the pig weigh 这头猪多重? -Eighty kilos.八十公斤。 3、how much 意为“多少钱”时,可单独使用,也可构成词组how much money,但英语中常省略money,用来询问某物的价钱、价格。 (注意:how much询问价格时,它的回答若是中国的货币单位应采用汉语拼音yuan,fen来表示,几角常采用几十分来表示,字母用小写,且不用复数。4、用来询问数字计算的结果,相当于what。How much is three plus one 三加一等于多少?  It s four.等于四。
表数量的不定代词many和much具有名词和形容词性质,在句中可用作主语、宾语、定语等,都意谓“许多”、“大量”;它们的不同在于:many只能指代或修饰复形可数名词,much一般只能指代或修饰不可数名词。1)常用于疑问句、否定句,或if或whether引导的宾语从句。如:Do you know many people in London? 你在伦敦认识很多人吗?Did you have much rain of your holidays? 你休假时遇上很多雨吗?I did not meet many English people who could speak foreign languages. 我遇见能讲外语的英国人不多。I did not have very much advice to give him. 我对他提不出很多忠告。I wonder if many people will come to the party. 我不知道会不会有很多人来参加聚会。I doubt whether therell be much time for seeing the sights. The train leaves at six oclock. 我怀疑会有很多时间去观光。火车六点就开。2)在日常英语的肯定句中,用a lot of,lots of,plenty of,a great deal of,a large number of,a good many和a great many等来代替many和much。Theres still a lot of work to do before we leave. 在我们走之前还有很多工作要做。She knows lots of girls who go out dancing every Saturday. 她认识很多女孩,她们每星期六外出跳舞。I know plenty of boys in other schools had achieved the same results as I had. 我知道其它学校有很多男孩已取得与我同样的成绩。He has done a great deal of research on the subject. 关于这个题目,他已经做了很多研究工作。A large number of people were gathered at the café. 咖啡馆里聚集着很多人。My mothers family had been different in a good many ways from my fathers. 我的母系家庭与我的父系家庭有很多不同。A great many mistakes have been made by nearly everybody. 几乎人人都做错了很多。3)当many和much有程度副词so,too,as,how等修饰时,可用于肯定句。如:There are too many mistakes in your exercises. 你的练习中错误太多。No, I wont do it. Its too much trouble. 不,我不会干这种事,麻烦太多。Ive got so many jobs to do today. 今天我有这么多活要干。Take as much milk as you want. 牛奶你要多少就拿多少。How many hours does it take? 要花多长时间?4)many和much相当于名词时,常后跟of短语。如:Not many of the delegates vetoed the plan. 否决这项计划的人不多。There were lots of people on the beach, not many of whom were holiday-makers. 海滩上有很多人,但度假者不多。Not much of the time was wasted. 浪费掉的时间不多。5)many和much有共同的比较级形式more和最高级形式most。如:I found more letters lying on his table today. 今天我发现他桌上有更多的信。He made more progress than I expected. 他取得的进步超出我的预料。He knew more about me than I thought. 他对我的了解比我想像的多。I shall write and tell you if I want any more. 如果我还要,就写信告诉你。You must go right off and get some more. 你必须马上去,再弄一些来。Most people hold the same opinion as you do. 大多数人持与你相同的观点。Most work was done in my fathers offices. 大多数工作是在我父亲办公室干的。The most I can do for you is to give you a letter of recommendation. 我能为你做的最多是给你一封推荐信。Most of the delegates voted against the proposal. 大多数代表投票反对这项提议。Most of his relatives lived in the country. 他的大多数亲属住在乡下。Most of his money came from selling his landscapes. 他的大多数钱来源于出卖他的风景画。希望我能帮助你解疑释惑。
1.i have got far too much to do.我要做的事情太多了。 it is not much of a day for a walk.这不是个散步的好日子。2.i have many good friends.我有很多好朋友。 our school have many students.我们学校有很多学生。3.i know few people understand the difference.我知道很少有人 了解这个差别。 i have had a few answers.我已得到了一些答案。4.here is a little something for your birsday.这是我送给你的 生日礼物。 my little sister is 5 today.我的小妹妹今天五岁了。
首先要弄清楚他们的意思及区别many +可数名词的复数 many booksmuch +不可数名词 much money

什么时候用much什么时候用many在句子中


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