目佳先生在“英语语法网”(www.yygrammar.com/Article/200812/1057.html)发表了自己的看法：
看法之一《薄冰高级英语语法》(世界知识出版社2002年9月第7次印刷) 第16.8节“状语从句”：方式状语从句(adverbial clause of manner)：方式状语从句表示动作的方式，其所用的关联词有 as, as if, as though, the way, how 等，多位于主句之后。例：(143)He looks as if he’s tired. 他像是累了。
我们认为 He looks as if he’s tired. 中的 as if 引导的从句不宜分析为方式状语从句，而应分析为表语从句。因为 look 在此为系动词，而非实义动词，它后面应接表语，意义才完整。另外，《薄冰高级英语语法》认为“方式状语从句表示动作的方式”，而He looks as if he’s tired.中根本没有“动作”动词，所以也就无所谓“动作的方式”。
看法之二：《朗文英语语法》(外语教学与研究出版社2002年3月第16次印刷)第
I feel as if / as though I’m floating on air. 我感到好像漂浮在空中一样。
注意：也可以用在 it 结构后面：
It sounds as if / as though the situation will get worse. 听起来好像情况会恶化似的。
It feels as if / as though it’s going to rain. (i.e. I feel that this is going to happen) 这天气给人的感觉好像是就要下雨了。(即我感觉这事即将发生。)
我们认为说“方式状语从句在动词 be (是，feel (感觉)，look (看) seem (好像)，smell (闻)，sound(听起来)，taste (尝起来) 等后面也可以由连词as if和as though来引导”似乎不妥，因为be (是)，feel (感觉)，look (看)，seem (好像)，smell (闻)，sound (听起来)，taste (尝起来)等都是连系动词，它们后面接的 as if / as though 从句应是表语从句，而不是方式状语从句。
实际上，中外的语法专家几乎都一致认为上述提到的动词 be (是)等之后所跟的as if / as though 从句是方式状语从句，而不是表语从句。请看例证：
1. 张克礼在《英语语法难题集释》(天津人民出版社 1988年9月第1版)p455上进行了明确的阐述：
问：You look as if you slept badly. 中 as if 引导的是状语从句还是表语从句？
答：是状语从句。look在这里不是连系动词，而是全动词(连系动词作实义动词时，称全动词)。
Quirk在谈到这类从句时说as if 和as though引导表示有假设情况的比较状语从句( as if and as though introduce adverbial clause indicating comparison with some hypothetical circumstance.―p755 )
He looks as if he’s sick: fetch the doctor.
Curme 说：它们(动词look, seem 和be)不是连系动词(copulas)，而是全动词(full verbs)(p.282):
He looks(=have an appearance, acts) as if he were going through a great crisis.
They seemed(=seemed to act) as if they had never missed Sylvia.
It seemed to me(=impressed me) as if they had never missed Sylvia.
It was(seemed) almost as if people had sensed at once that she could never be held accountable for what she said and did.
Palmer 也认为在这种结构中 be, look, seem为实义动词，并与其他可用于这种句型的实义动词相提并论，说这种句型主要动词有：act, appear, be, behave, feel, look, seem, sound, talk, taste, treat(sy. 或sg.)(p.283)：
It looks (behaves, seems, etc.) as if it were here. (it would rain, etc.)
Kruisinga 也认为as if-从句为比较状语从句：
And it certainly looks as if something dreadful would happen to Miss Thong.(Part II, 3 p.413 )
与此相似， “It seems，etc. that ”结构中的seems等也是实义动词。that-从句为主语从句，it为形式主语。Hornby说that-从句出现在seem， appear, happen, chance和 fellow后时，前面的it为先行it(introductory it)(p.23):
It would seem (that) the rumours have some truth in them.
It appears (that) the plane did not land at
It seemed (to me) (that) you’re not really interested.
Could it be that the sound of her heart beat is vital factor? (English Through Reading p.32)
It may be that in having that I am really wise.(ib., p.131)
It cannot be that he was speaking falsely for he was a god and can not lie.(ib., p.132)
但是，LDCE认为seem, appear等的这种用法为实义动词，be为连系动词(实际上be与上述动词用法一样，没有必要把be分出来):
It seems (=appears to be true) as if there will be an election soon.(p.1007)
It would seem that there is no way out of our difficulty. (ib.)
It appears (=seems to be true)(that) she will win.(=It appears as if she will win.)(p.39)
It’s (as a connecting verb) as if we had never even started.(p.77)
连系动词与不及物实义动词是不同的，连系动词必须接表语，不及物动词意义本身就完全了。seem, appear等作连系动词时，that-从句既可以放在句首又可放在句末；作实义动词时，that-从句不能放在句首，只能放在seem等后：
It seems doubtful that he will be on time. (Liles p.123)
2.【日】绵贯阳等著《现代英语语法例解手册》(修订版)（申勇译 科学出版社 2000年2月第一版）p612-613引导方式状语从句的连词：
The man looked as if he hadn’t slept for a week. (这个男人看上去就像一个星期没睡觉了。)
She looks as if she is getting better.(她看上去像是好多了。)
尽管中外的语法专家几乎都一致认为上述提到的动词 be (是) be (是)，feel (感觉)，look (看) seem (好像)，smell (闻)，sound(听起来)，taste (尝起来) 之后所跟的as if / as though 从句是方式状语从句，而不是表语从句，但近年来，有的语法专家的观点发生了转变，即他们认为是表语从句。请看例证：
1. John Sinclair主编《柯林斯COBUILD英语语法句型1：动词》(上海外语教育出版社 2000年11月第1版)p121: These verbs (笔者注：指appear, look, sound, feel, smell, taste)are used to indicate how someone or something seems. They are all link verbs.
He felt as though he had run five miles.
Isabel’s voice sounded as if she had been crying.
笔者注：既然认定是连系动词，那么其后面的as if/though从句确定无疑是表语从句。
2. 王国栋编著《大学英语深层语法》（清华大学出版社2005年1月第1版）p645: 动作动词behave, act, walk等后面接as if/ as though引导方式副词从句；接在系动词或半系动词（包括五官感觉动词）之后是表语从句。系动词或半系动词引导表语从句：be as if 是像，look as if 看起来好像，sound as if听起来好像，smell as if嗅起来好像，taste as if尝起来好像，feel as if摸起来好像，seem as if 思想觉着像，appear as if 表面看着像
从以上可以看出：尽管大多数语法专家认为be (是)，feel (感觉)，look (看) seem (好像)，smell (闻)，sound(听起来)，taste (尝起来) 之后所跟的as if / as though 从句是方式状语从句，而不是表语从句；但有极少数语法专家认为是表语从句，且分析为表语从句似乎比方式状语从句更有道理，更便于理解，因此，相信不久的将来，会有更多的语法专家会摒弃“方式状语从句”的看法，接受“表语从句”的观点。
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