有读者问：如何解释下面句中的 as they do？
(1)Living as they do in such poverty it is not surprising that the women of Iraq were able to send only five delegates to Lausanne.
句中的“现在分词+as+代词主格+替代词do”结构是英语书面语中较为常见的一种结构。这种结构与其中的现在分词一样仍表原因、理由、根据等，“as+代词主格+do”在此只起一种强调现在分词的作用。上述例（1）中的 living as they do 即是一例。这里的现在分词短语 living as they do in such poverty 即表示原因，说明为什么伊拉克妇女只能派出五名代表参加洛桑的世界妇女大会。再如：
(2)Living as I do so remote from town, I rarely have visitors.
这种结构亦可置于句末和句中，如：
(3)I feel it to be a rare occasion, occurring as it does only once in many years.（位于句末）
(4)This harsh letter, coming as it did from a man generally so polite and respectful, struck a mortal blow at the pride of Villefort.
在上述“现在分词 + as + 代词主格 + do”结构中，do 除可用其现在一般时与过去一般时外（见上述诸例），有时也可用其他时态，如下面一句即用的是完成时态：
(5)Living as he has done for many years in the country, he, like many other Manchester businessmen, divided his time and interests between the city where he worked and the country where all his leisure was spent.
现在让我们对上述结构做一点语法分析。这里的-ing形式显然是现在分词而不是动名词。as是连词，其本义是“如同”。它在此引导一个比较状语从句。这种结构中的 do 当然是替代词，用以替代其前的现在分词。前后一般不用逗号，但有时也可用逗号，以表示一种较为松散的结构，如：
(6)How should I hear anything, living as I do , tucked away in a corner?
“现在分词+as+代词主格+do”除表原因外，有时亦可表让步，如：
(7)Munching as he did the apple, he had an eye for John's movements.
请注意下面两句中的-ing形式则不是现在分词，而是动名词：
(8)I can't help looking as I do .
(9)Only by listening as he was doing now , could Adam judge the quality of communication between Smokey Stephenson's dealership and its clients.
顺便提一下“过去分词+as+代词主格+be”结构，如：
(10)Involved as he is with his own problems, he hears nothing.
这里的 Involved as he is with his own problems,...是一过去分词短语。过去分词和前面所讲的“现在分词+as+名（代）词+do”结构中的现在分词一样，也表示原因，as he is 也起一种强调过去分词的作用，as也是连词，用以引导一比较状语从句的省略结构。这种结构也常用在书面语中，再如：
(11)Burdened as she was , it would be impossible to climb down the steep iron stairs.
(12)Isolated as we are , I shouldn't think there would be any germs. The wind always seems so fresh.
(13)Impressed as we were with this “real-life” encounter with day-to-day people, our impressions of China as exotic and far away no longer held.
(14)This man was more than six feet tall, broadshouldered, about as welcoming as iceberg. More like the island's forbidding cliffs, Polly thought, covered as he was in a black water proof.
但当过去分词近似于形容词时，上述结构也可表示让步，如：
(15)Worn out as they were , smiles and satisfaction showed on their faces.
请注意，“过去分词+as+代词主格+be”结构中的代词主格有时可代之以名词，如：
(16)Hampered as education and progress was by the “Cultural Revolution”, teachers are frantically writing lessons and books as they teach classes, and tradesmen are learning skills in building construction lost during that period of instability.
最后，还应指出两点：
1. “as+代词主格+替代词do”结构是一种常见说法。它常被独立使用，并不经常与分词连用，如：
(17)He showed no trace of nervousness now, as he had done at our first meeting a few days before.
2. 下面一句中的 as 并非连词，而是关系代词，二者不可混淆：
(18)In my future work this subject will be treated, as it well deserves , at greater length. （顺便指出，as 用作关系代词时，其后不可用替代词 do）
