Paul then took a taxi to another shop where he bought several pairs of leather shoes and boots.
VOA: special.2009.04.11
So oxygen gets 3 pairs, and each chlorine gets 3 pairs, so now we're up to 9 pairs.
那么氧都有三对,每个氯有三对,那么现在我们用了九对了。
so I really learned to enjoy working in pairs and with my classmates.
所以我真的喜欢上了跟我的同学两人合作。
Well, we're talking about a pretty high number here, so to make counting easier, we'll just say 10 lone pairs, because 20 lone pair electrons is the same thing as 10 lone pairs.
好吧,我们这里讨论的是一个挺大的数,为了数起来更容易,我们就说有十对孤对电子,因为二十个跟十对是一个意思。
This is my humble drawing to indicate discrete sodium chlorine pairs.
我画的比较丑,想表示不连续的氯化钠对。
The question was how many rabbits do you have at the end of a year? At the end of two years? At the end of more than that number of years, and so. We can do this with the following level definition. We're going to let pairs of 0, the number of pairs at month 0, actually it would not be it would be 1.
在下一个月末的时候让我们假设,这2只小兔子也有了后代,同样是一公一母,问题是一年后你会有多少只小兔子?,两年后呢?更多年后呢?,我们可以用接下来的等级说明来解释,在第0个月有0对兔子。
Now if you read in the book, you read about where this figure is shown in the book, you can understand more about why these structures line up in the right way so that the right molecular elements are together to form hydrogen bonding pairs between them.
如果你预习过课本,课本中有关于这些详细的描述,你可以更深刻的理解,为什么这些结构是采用这种连接方式,以使对应的分子部分靠近,并形成氢键连接
PROFESSOR: Good, good, it's going to be less than, and it's going to be less than because now we have two lone pairs.
教授:很好,它要更小,因为我们现在有两个孤对。
So since we have two lone pairs, we're going to be pushing down even further on the bonding electrons, so we're going to smoosh those bonds even closer together.
因为我们有了两个孤对,我们会把成键电子,更加向下压,所以我们把这些键更加紧得推到一起。
And step seven is how many electrons do we have left over that are going to go into lone pairs? How many?
而第七步是我们剩下,多少电子成为孤对电子?多少?
0. 26 minus 6, so that tells us 20, and these are all going to be lone pairs.
二十个,二十六减去六,因此是二十个,它们都会成为孤对电子。
So the access that a cell has to certain kinds of genes, or chemical modifications of DNA, not chemical modifications that change the base pairs, that would be a mutation.
因此细胞变化的途径应该是对某些基因,或者DNA进行化学修饰,不是更改碱基对,更改碱基对就是突变了
The goal of that was to take for a typical human, or for a typical - in the case of the human genome project maybe you're looking at fruit flies, you want to look at all the DNA in a fruit fly, but to look at the sequence of base pairs that makes up human DNA and write them all out; we'll talk about that later.
这个计划的目的是,建立一个有代表性人类的基因顺序,或者说是典型的人类基因组,就人类基因组计划来说,或许你在研究果蝇,你想观察果蝇内的所有DNA,而人类基因组计划是观察组成人类的,DNA的碱基对顺序并且将它们记录下来,我们不久之后会讨论这些内容
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