SAT2 | 玄数

2018-12-28

SAT Ⅱ

A four-digit pin number is needed to access a bank account. How many different four-digit pin numbers are possible if no number can be used twice, and the first and third digits must be odd, and the second and fourth digits must be even?

Answer
400. 访问银行帐户需要四位数的密码. 如果没有数字可以重复使用, 而且第一个和第三个数字必须是奇数, 第二个和第四个数字必须是偶数, 可以有多少个不同的四位数密码?

一、状语和条件、让步状语从句的对比

1.  简单句中的状语

He is ready to help you. …………… 他已经准备帮你了。
Given more time, we could done the work better. ……. 如果提供更多的时间,我们会做得更好。

2.  条件、让步状语从句

I’ll go out tomorrow unless
it rains.
我明天外出,除非下雨。 (条件)
I’ll go out tomorrow even if
it rains.
即使明天下雨,我还是外出。 (让步)
(主语 + 谓语+ 状语) 引导词 (主语 + 谓语)

it rains 已是“主谓”结构的语句,通过引导词作引导成为状语从句来修饰 “I’ll go out tomorrow”,引导词不同,整个句子表达的意思也就不一样

二、条件状语从句

条件、让步状语从句由从属连词 if、 unless ( = if not ) 、 as long as ( = so long as ) 引导

if:如果

unless ( = if not ) :除非,如果不

as long as ( = so long as ) :只要

He will come if you invite him. …………… 如果你请他,他会来的。
If I were you, I would go to see Mr.Lee at once. …………… 如果我是你,我会马上去找李先生的。
 
I’ll go out tomorrow unless it rains.  =  I’ll go out tomorrow if it dose not rain.
我明天外出,除非下雨。(如果明天不下雨,我会外出。)
 
I wouldn’t give up unless he give up first.  =  I wouldn’t give up if he doesn’t give up first.
我不会放弃,除非他先放弃了。
 
As long as you drive carefully, you will be very safe. …………… 只要你小心驾车,你会很安全的。
There is hope so long as he is with us. . …………… 只要他在就有希望。

三、让步状语从句

让步状语从句可由 though ( = although) 、 as、 even if ( = even though ) 、 whether … or not 、 no matter ( what、 who、 when、 which、 where、 how )

1.  though = although:虽然。 一般 although 只用在句首,而 though 可用在句中任何位置,他们都不能够与 but 连用

Althought ( Though ) he is young, he knows much. …………… 虽然他年轻,但他懂得很多。
He knows much though he is young.
He is young, but he knows much.
Althought ( Though )he is young, but he knows much. …………… (×)

2.  as:尽管,用倒装

even if ( = even though ) : 尽管,即使

whether … or ( not ):不管怎样,无论如何;
不论 … 还是 …

Cold as it was, we went on working in the field. …………… 尽管天气冷,我们继续在田里干活。
Tired as he was, he sat up late. …………… 他虽然疲倦,可仍然熬夜到很晚才睡。
 
I’ll go out tomorrow even if it rains. …………… 即使明天下雨,我还是外出。
Even though he tried, he still lagged behind other runners.
尽管他努力了,仍落在其他赛跑者之后。

I’ll go out tomorrow whether or no it rains. …………… 无论是否下雨,我明天将会外出。
Whether they go or stay, it makes no odds. …………… 他们是去是留都没多大关系。

3.  no matter ( what、 who、 when、 which、 where、 how ) :不论 ( 什么、谁、什么时候、哪一个、什么地方、如何) ,可以由 ~ever 构成的合成词替代

No matter what happens, I’ll always love you.  =  Whatever happens, I’ll always love you.
无论发生什么,我将永远爱你。
 
No matter who break the law, he will be punished.  =  Whoever break the law, he will be punished.
不论谁犯法,都要受到处罚。
 
No matter when you come, you’ll be welcome.  =  Whenever you come, you’ll be welcome.
无论你什么时候来,都欢迎。
 
No matter which they choose, we must accept their decision.
Whichever they choose, we must accept their decision.
不论他们选择哪一个,我们必须接受他们的选择。
 
No matter where she goes, there are crowds of people waiting to see her.
Wherever she goes, there are crowds of people waiting to see her.
不管她去到那里,总会有一群人在等她。
 
No matter how hungry I am, I never seem to be able to finish off a whole pizza.
However hungry I am, I never seem to be able to finish off a whole pizza.
无论我多么的饥饿,我似乎从来没有能够完成一整个比萨。

练习

翻译:
cylinder     圆柱,柱面
A right circular cylinder having a finite height with circular ends perpendicular to the axis as shown in the figure. If the ends are open, it is called an open cylinder. If the ends are closed by flat surfaces it is called a solid cylinder.

 
ellipse   椭圆
A closed, symmetric curve shaped like an oval, which can be formed by intersecting a cone with a plane that is not parallel or perpendicular to the cone’s base. The sum of the distances of any point on an ellipse from two fixed points (called the foci) remains constant no matter where the point is on the curve.

条件、让步状语从句 if