【问】 As it happens，we probably won't have all that much time for a holiday，though.
 许多语法书上都指出，as可作关系代词，引导非限制性定语从句，它在其中充当主语、宾语等。上面的句子里在as之后又加上了充当主语的it，是不是错误的?
 【答】 as可以引导定语从句，包括修饰句子的定语从句(sentential relative clauses)。这种从句可放在句首、句中或句末。
 1. As has been said above，a magnet produces a magnetic field in the space around itself.
 如上所说，磁铁在其周围的空间会产生磁场。
 2. Spiders are not insects，as many people think，nor even nearly related to them. (NewConcept English，Book 4)
 蜘蛛并不象许多人所认为的那样是昆虫，它甚至与昆虫没有任何关系。
 3. In electrical usage the term potential，as will be pointed out later，has a definite quantita-tivemeaning.
 在电学上，正如以后将要指出的那样，电位这个术语具有确定的数量意义。
 所以常常可以看到下面这样一些含有关系代词as的定语从句：
 as everybody knows，as you may remember，as you say，as I can see，as I have said，asI’m told，as you may have heard
 有的英语语法著作(如葛传椝：《英语惯用法辞典》，P.64)据此便把as it happens这类句子斥为错误用法。例如，他们说下列句子里的“it”“是要不得的”：
 “1. The author was brought up in a small village，as it is recounted in some of his stories.
 2. As it is announced in today’s papers，all the schools will reopen on 1 September.”
 然而，英语的实际使用情况并非如此。事实上，许多作者都愿意在这类句子里加上一个“it”，来代表整个句子、句子一部分或名词短语，而把as看作是从属连词：as it happens，as itappears，as I see it，as I interpret it。这就是说，上面的两种结构都是正确的。下面我们列举一些例句来证明这一点：
 1. As it appears from her essay，she has read widely in Romantic literature. (CGEL)
 从她的文章看，她好象阅读了大量的浪漫主义文学作品。
 2. He is the best candidate，as it seems. (CGEL)
 他好象是最佳的侯选人。
 3. As it happens，we probably won’t have all that much time for a holiday，though.
 但是，碰巧我们的假期不会有那么长的时间。
 4. Our difference，as I see it，is one of method and not of principle.
 在我看来，我们的分歧是方法上的，而不是原则上的。
 5. As I see it，this article is quite well-written.
 在我看来，这篇文章写得很好。
 (参见it¹²)