4. The beatles brought western pop music to audience around the world as they went out on tours and played concerts in many different countries.

随着甲壳虫乐队在许多国家进行巡回演唱会，他们把西方流行音乐带给了全世界的观众。

【巧解句构】句中as they went out on tours...是一个以as引导的时间状语从句，表示"随着......，当......的时候"。

【拓展延伸】as的用法归纳如下：

1）用作连词可引导比较、让步、时间、原因等状语从句。如：

As he looked at her, she made a face.

他看她时，她作了个鬼脸。（时间状语）

As he didn't know much English, he got out his dictionary and looked up the word.

由于他不懂多少英语，因此他拿出来词典查了这个单词。（原因状语）

He doesn't speak as the other people do.

他不像其他人那样讲话。（方式状语）

He is not so diligent as you.他不如你勤奋。（比较状语）

Young as he is, he knows a lot.

尽管很年轻，但他懂得很多。（让步状语）

2）作关系代词，引导非限制性定语从句，先行词前常用such, the same与之呼应，构成such...as...,the same...as...。如：

We'll make such computers as are needed in different branches of science.

我们将制造出各科学部门所需要的那种计算机。

I am reading the same book as you.

我们读的是同一本书。

3）作关系代词引导非限制性定语从句，as指前边或后边的整个句子。如：

As you can see in the map, the two cities are far away from each other.

如你在地图上所见，两座城市相距甚远。

As everybody knows, all that glitters is not gold.

大家都知道，闪光的东西不都是金子。

4）prep.作为；当......的时候

You will be welcomed as a hero tomorrow morning.

明天早晨你将作为英雄而受到欢迎。

As a young boy, he lost his parents in the war.

当还是个小孩时，他就在战争中失去了双亲。

【辨析比较】1)as和which

as和which在引导非限制性定语从句时，这两个关系代词都指主句所表达的整个意思，且在定语从句中都可以作主语和宾语。但不同之处主要有两点：①as引导的定语从句可置于句首，而which不可。②as代表前面的整个主句并在从句中作主语时，从句中的谓语常为系动词；若为行为动词，则从句中的关系代词多用which。as可引导非限制性从句，常有"正如"之意。如：

①As we know, smoking is harmful to one's health.

②As is known(to us),smoking is harmful to one's health.

as 是关系代词。例①中的as作know的宾语；例②中as充当从句的主语，谓语动词know要用被动式。

2)when, as和which

①when从句表示某时刻或一段时间，如：