as引导定语从句的省略问题
有网友问，下面句中As already mentioned好像不完整，mentioned的逻辑主语是什么？
As already mentioned, the legislation does not consider low pay as an acceptable reason for turning down a job.
这里不存在逻辑主语的问题，而是省略了某个成分。众所周知，英语在朝着表达简洁的方向发展，我认为，as的这种用法其实是一种省略现象。以下两种解释都可接受：
第一、把as看作关系代词，指代后面整个主句的内容，as是定语从句的主语，后面省略了is。因此，As already mentioned等于As is already mentioned。
第二、把as看作从属连词，引导方式从句，意为“像......那样”，as之后省略了it is，it指代整个主句的内容。因此，As already mentioned等于As it is already mentioned。
能用于此句式的动词，一般都是“陈述，叙述，描述，提及，说及，显示，指出”之类的词，多用于议论文体，是带有总结性的提示语。除了As already mentioned以外，常见的有：
1. as already said 简笔画山水正如已经说过的（那样）
2. as already mentioned 正如已经提到的（那样）
3. as already described 正如已经描述的（那样）
4. as already discusd 正如已经讨论过的（那样）感恩演讲稿3分钟
5. as already noted 正如已经叙述到的（那样）
6. as already stated 正如已经指出的（那样）
7. as already announced 为什么抽烟会上瘾正如已经宣布的（那样）
8. as already pointed out 正如已经指出的（那样）
9. as already indicated 比喻句怎么写如前所示（那样）
10. as already hinted 正如已经暗示的（那样）
11. as already told 正如已经告知的（那样）
12. as already shown 如已显示（那样）
13. as already emphasized 正如已经强调的（那样）
14. as already obrved 正如已观察到的（那样）冬天去哪旅游
15. as already explained 正如已经解释过的（那样）
16. as already suggested 一往无前的近义词正如已经提出的（那样）
例如：
Another problem here is that -- as already mentioned -- you will have to construct this XML by hand. 这里的另一个问题，前面已经提到，即必须手工创建XML描写绿色的词语。
As already noted, there are many ways of depicting average income, including per member of the population, per worker, or per hour worked. 气候分布图如前所述，反映平均收入有许多方法，包括每个人口，每一工人，或每一工时的平均收入。
Customers, as already discusd, have different goals than urs. 正如已经讨论的，顾客有不同于用户的目标。
The form of marriage, as already said, was a pairing marriage which was gradually approaching monogamy. 如前所述，婚姻的形式是逐渐接近一夫一妻制的对偶婚制。
As already indicated in Sec. 4.3 we e this as a possible direction for a future breakthrough. 诸如在4.3节中所指明的那样，我们看到这是在未来进行突破性研究的可能方向。
As already suggested, lawsuits do not begin themlves. 正如已经指出的那样, 法律诉讼不会自行开始。
