1)是名词 seeing
is believing
2)具有动词性特征可以带宾语 starving troops
is necessary.
一)动名词的形式:
一般形式：I don't like you smoking.
完成形式：I regret not having
taken your advice.
被动形式：This question is
far from being settled.
二) 动名词常考的点
1)动名词做主语谓语动词为单数
2)在动名词和不定式中,做为介词的宾语是动名词
3)动名词的否定直接在其前加否定词,通过代词的宾格或所有格形式给出逻辑主语.
I would appreciate_______ back this
afternoon．
A．you to call B．you call C．you calling D．you're calling(Key：C your calling 也对)
I regret not having taken your
advice.
4)有些词后只能接动名词
admit; appreciate; avoid; celebrate;
consider; contemplate; defer; delay; deny; detest; discontinue; dislike;
dispute; enjoy; it entails; escape; excuse; explain; fancy; feel like; finish;
forgive; can't help; hinder; imagine; it involves; keep; it means; mention; mind; miss; it
necessitates; pardon; postpone; practice; prevent; recall; report; resent;
resist; risk; suggest; understand...
另外还有一些接-ing形式的常用说法：
it's no good; it's no/little/hardly any/
use; it's not/hardly/scarcely use; it's worthwhile; spend money/time; there's
no; there's no point in; there's nothing worse than; what's the use/point...
5有些词后加不定式和动名词均可
remember, forget, try, stop, go on, cease, mean后面用不定式和-ing形式，意义截然不容。
I remembered to
post the letters. (指未来/过去未来的动作)
I remembered
posting/having posting the letters (我记得这个动作)
forgot与remember的用法类似。
I regret to
inform you that… 我很遗憾地通知你…
I regretted
having left the firm after twenty years. 为了"二十年前的离开"而遗憾。
try to 努力 You really must try to
overcome your shyness.
try –ing 试验 Try
practicing five hours a day.
I mean to
go, but my father would not allow me to. [打算、想]我想去，但我父亲不让我去。
To raise wage means
increasing purchasing power. [意味着]赠加工资意味着增加购买力。
prefer的用法：
我宁愿在这里等。
I prefer to
wait here. (所以啊，你不介意的话，我就等下去。)
I prefer
waiting here.(我正在这里等，我就喜欢这么做。)
I prefer
swimming to cycling. (这个句子里面就不能用不定式了。)
3 分词：
现在分词主动进行,过去分词被动状态
现在分词的形式:
1)一般式: Do
you see the man talking to the dean(主任)? (与谓语动词同步发生)
2)完成形式：Not having made adequate preparations,
they failed. (发生谓语动词之前)
3)完成被动形式：Having been adapted, the script seems
perfect.( 发生谓语动词之前且表示被动)
过去分词
1) 过去分词表示被动：Fight no battle unprepared.
2)过去分词的进行形式：You'll find the topic being discussed everywhere. (强调正在被做)
这三种非谓语动词，都可以构成复合结构，非谓语动词所修饰的成分是这些非谓语动词的逻辑主语。他们之间的一致关系--主动还是被动，往往就是考点。独立主格结构中，要注意的是分词与他前面的逻辑主语之间的主动被动的关系。
二：虚拟三：虚拟语气
情态动词所表达的可能性程度：must/can't
à should/shouldn't à might/may (not)
另外两个"类情态词的形式："need/needn't; have to/don't have to
v
最自然的虚拟状态：由should/would+原型时态(不含时间只含状态)
本质上是过去将来时：即，时间固定在过去将来，状态不同：一般、进行、完成、完成进行。
这时"虚拟语气"的产生往往是因为我们要表达"本来应该……"(而现在却还没有……)
(本来可以……，本来能……)
I should go! (… but I'm still here!) (一般)
I should be
working now! (进行)
I should have
practiced more (than I did)! (完成)
我应该多多练习！(言下之意，现在我练习得不多。)
I shouldn't
dream away my time too much! (完成的否定)
(actually I did
dream away my time too much!)
It shouldn't
have been leaking for such a long time! (完成进行)
I
may/might/could have finished! (完成)
一些常见的句型中，就会出现这种虚拟语气，而处于从句之中，should 常常被省略掉
o
suggest, advise, propose,
recommend, plan;
o
demand, order, direct, arrange,
command, decide;
o
require, request;
o
think, expect, believe, insist,
suspect.
由于他们的含义中包含"建议，假设，应该"这类的含义，所以，由他们引起的从句中，就会包含有should+原型时态构成的虚拟语气。
这些动词(以及他们的名次形式，分词形式)引起的从句还有其他的变形：
主语从句，表语从句，同位语从句
It's suggested
that…
My suggestion is
that…
The only
suggestion that...
The only
suggestion I can give you now is that…
一些形容词引起的表语从句中，也会有同样的情况
important;
necessary; essential
It's natural ; strange; incredible that
a
pity; a shame; no wonder
Ø
由lest, for fear
that, in case 引起的从句中多使用should
v
表达与事实相反
1. 与现在相反：使用[过去时]：
I wish I were not here! (一般现在à一般过去)
Suppose we were not here.
He loved me as if I were his own son. (一般现在à一般过去)
Hope I weren't always losing things! (现在进行à过去进行)
If only/If I hadn't been there! (现在完成à过去完成)
What if I hadn't been waiting right here! (现在完成进行à过去完成进行)
常考句型：It's (high) time (that)…; would rather (that)…
这两个从句，只能表达对现在的看法，所以，从句中只有一般过去时。
