有一读者问： 有这样一句话：
(1)Linda is buttoning up his jacket as he unbuttons it.
请分析一下句子末尾的as从句，并解释一下它的意思。
对于作“如同”或“像”解的连词as，当它引导一种肯定结构时，我国学生是比较熟悉的，至少是觉得容易理解的，如：
(2)Alone with Lamin, as he sometimes was, Kunta might pay his brother a bit more attention.
(3)The winners play each other tomorrow, as do the losers.
(4)Gradually his memory slipped a little, as memories do, even those with so much love attached to them.
我国学生对“否定结构+as+肯定结构”这样的句型也是能够理解的，如：
(5)His beard was no longer black, as it had been in the picture.
(6)We do not want our children to suffer war any more as we have suffered it.
但如遇到“肯定结构+as+否定结构”这样的句型，我国学生就不很熟悉甚至觉得难以理解了。上面所提问的句子就属于这种句型。这种句型中的连词as不但意谓“如同”或“像”，而且有表对照或对比的转折含义。上述句（1）的本义是：Linda在把他的上衣扣上，正如他常把他的上衣解开一样。而其实际含义则是：Linda在把他的上衣扣上，而他却常是把他的上衣解开的。这种表示对照或对比的句型并不罕见，再如：
(7)We are enjoying ourselves as we have never enjoyed ourselves before!
(8)You can hurt me as I cannot hurt you.
(9)And then there would be a child — a boy, whom he could...love as he did not love Charles.
(10)I felt, as I never had before, that without warning he might turn against me.
(11)Keith knew — as others did not — that the real responsibility for the tragedy was his own, not Perry Yount's.
(12)Mat had taken to that young woman as he did to few people.
有时as还可引导一个修辞性问句，如：
(13)Adele had often pictured her wedding to herself, as what young girl has not.
最后，还应该指出，as也可以在“肯定结构+as+肯定结构”的句型中表示对照或对比，如：
(14)He dreaded, as he hoped, to find her.
(15)You know that my fortunes have sunk as yours have risen.
