虽然他累了，但他继续工作。
Though / Although he was tired , he went on working.
Tired as / though he was , he went on working.
He was tired , but he went on working.

一、though和although的区别

1. although较正式，语气强；though较常用。现代英语中两者可随意换用。如：Though he was tired, he went on working. =Although he was tired, he went on working.

2. although和though引导的从句放在主句前后均可，有时还可放在句中。如：He often helps me with my English (al)though he is quite busy. 尽管他相当忙，但是还常常帮我学英语。Although many difficulties are still ahead, we are determined to make greater achievements. 尽管在前面的道路上还有许多困难，但是，我们决心要取得更大的成就。

3. although/though引导的从句不能与but/however连用，但可与yet/still连用。不能说：Though he was old, but he worked hard. 应把but去掉。当然，保留but而去Though也可。

4. though有时指假设的情况，不指事实，从句用虚拟语气；although不能这样用。如：Einstein cared little for money, though he could have been very rich. 尽管爱因斯坦本可以成为非常富有的人，但他对金钱却不感兴趣。(though引导的情况是假设的而不是事实）He will never do such a thing though he (should) be forced to. 即使强迫他，他也决不会干这样的事。（注意：不能用is）

5. though引导的从句，可用倒装语序，即把从句中的表语或状语放到though之前；although却不能这样用。如：Young though she is, yet she is fit for the job. （=Young as she is, yet she is fit for the job.）尽管她很年轻，可她还是胜任这项工作的。

6. though从句的主谓语若是系表结构时，可以省略从句主语和be动词。如：Though alone, he is happy. 虽然他独自一人，却很幸福。注意：Though loving him, I can not help him. 是错句。因为从句不是be构成的系表结构作谓语。应改为：Though I love him, I can not help him. 或 Though fond of him, I can not help him.

7. though还可与别的词结合使用，如even though, as though等；although则无这种搭配功能。如：I\'ll go and help them even though I stop my work. 即使我停下自己的活不干，我也要去帮助他们。

8. though还可作并列连词，相当于and yet（然而，可是），它引导的分句常对另一分句起补充说明作用；although则无这种用法。如：I wouldn\'t like to go to the evening, though they will invite me to. 我不想去参加晚会，可是他们要请我去。They now can do most of the things people can do, though most scientists agree that computers can not completely take the place of humans. 人们能做的大部分工作，计算机现在都能做，然而大多数科学家认为，计算机并不能完全代替人类。

9. though可用作副词，放在词尾。although却不可这样用。如：He said he would come, he didn\'t, though. 他说要来却没来。

二、as的用法

一，副词adv：

1. 跟...一样地,同样地 例如:I\'m as tall as him 我和他一样高。

2. 如同;例如 例如:There are lots of famous buildings as the Eiffel Tower and the Arch of Triumph. 这里有许多著名建筑如埃菲尔铁塔和凯旋门。

二，介词prep：

1. 作为,以...的身份 例如:He works as a tour guide. 他作为导游工作。

2. 当作 例如:She is a famous person as a actress. 作为一个女演员,她很出名

3. 像;如同 例如:The old woman was dressed as a young lady. 这位老妇人打扮得像一位年轻人。

三，连接词conj：

1. 像...一样；依照；像 例如:You ought to do as Paul tells you. 你应按照保罗吩咐的做。

2. 当...时 例如:As she was leaving the room she remembered that book. 她离开房间时想起了那本书。

3. 随着 例如:As the sun rose the fog dispersed. 太阳一出来,雾随之消失。

4. 因为 例如:We didn\'t know what to do as we were just visiting there. 我们不知道该怎么办，因为当时我们仅仅在那里作访问。

5. 虽然 例如:Tired as he was, he stayed up late. 他虽然疲倦，可仍然很晚才睡。

6.尽管 例如：Try as she might,Sue couldn\'t get the door open.尽管想尽一切办法，苏还是不能打开那扇门

四，代词pron:

1. (与such,the same,as等连用,引导关系从句)与...相同的事物(或人) 例如:

He has earned as much money as I have. 他赚的钱和我赚的一样多。

2. (引导从句,对前述内容作补充)本情况,该事实 例如:She has married again, as was expected. 她已再婚,这是意料中的事。

五：缩写词abbr：

1. =Anglo-Saxon 盎格鲁-撒克逊人;盎格鲁-撒克逊语;盎格鲁-撒克逊人的;盎格鲁-撒克逊语的

2. =antisubmarine 反潜艇的

3. =Asia 亚洲;亚细亚

4. =Asian 亚洲的;亚洲人;亚洲人的

六，英语中as……as的用法:

(1) 在否定句中，第一个 as 也可换成 so。

(2) 在该结构的两个as之间通常接形容词或副词的原级，但若涉及数量或程度，可用“as much+不可数名词+as”和“as many+复数名词+as”。

I haven’t got as much money as I thought. 我不像原来想像的有那么多钱。

(3) 第二个as后接从句时，该as通常为连词，但有时这个as还充当其后从句的主语或宾语，此时该as实为关系代词。如：

I gave him as much as he could eat. 他能吃多少，我就给了他多少。

(4) 该结构根据情况可用使用以下修饰语。如：(not) nearly, almost, just, nothing like, exactly, not quite, half, one-ten, twice, three times, 30 per cent等，并且这些修饰语必须置于第一个as之前，而不能置于其后。