主语补足语
主语补足语，英语语法，主动语态中的宾语补足语，可以转化为被动语态中的主语补足语。
主语补足语，语法家们各有不同的看法。有的把连系动词后面的部分称作表语;有的又把被动语态后的补足语称作主语补足语，与被动语态一起称作复合谓语。如果把带有宾语补足语的句子变成被动句，原来补充说明宾语的部分就变成补充说明主语了。
- 中文名称 主语补足语
- 外文名称 Subject complement
简介
主动语态中的宾语补足语，可以转化为被动语态中的主语补足语。
eg. They caught the boy stealing. (stealing 作为宾语补足语)
转化为被动语态The boy was caught stealing. (stealing转化为主语补足语)
关系
被动语态的主语补足语与主动语态的宾语补足语是密切相关的。例如:
(1) I saw him playing basketball yesterday.
(2) He was seen playing basketball yesterday.
句(1)中的含义不是我看见他，而是我看见他正在打篮球。playing basketball是宾语him的补足语。所以叫宾语补足语。
句(2)中的含义也不是他被看，而是别人看见他正在打篮球。这里的playing basketball是主语he的补足语，故称作主语补足语。主语和主语补足语一起称作复合主语。所以含有主语补足语的句子一般是被动语态，谓语动词是可以接复合宾语(宾语+宾语补足语)的及物动词。句首的主语就是主语补足语的逻辑主语。
形式
1. 动词elect, call, name, make, find, leave等后面常接名词用作主语补足语。例如:
① The dog is called Karl.
② Coal is sometimes called stored-up sunlight.
③ He was found the right man for the job.
2. 动词keep, make, paint, cut, burn, beat, wash, find, consider, wipe等后面常接形容词用作主语补足语。例如:
① The door was painted white.
② The old man was found weak.
③ The classroom is always kept clean every day.
3. 动词see, watch, hear, feel, listen to, look at, imagine等后面接分词用作主语补足语。例如:
① He is often heard reading English.
② The professor was seen making an experiment in the chemistry lab.
③ The glass was found broken.
④ The classroom was found crowded with people.
4.感官动词see, watch, hear, notice, feel, make等后面接带to的不定式用作主语补足语。例如:
① He was seen to come upstairs.
② Ice is known to be in a solid state.
③ The spy was ordered to be hanged.
5.介词短语用作主语补足语。例如:
① The books in the study must be kept in good order.
② He was found in good health.
③ English is considered of great importance for us.
6. as后面接名词、形容词、分词等用作主语补足语。例如:
① English is taken as a useful means for research work.
② The news is considered as true.
③ The stool is usually thought as having four legs
④ The vase is thought as broken.
7. 由what引导的名词性从句用作主语补足语。例如:
The boy has been made what he is.
判别方法
1.看句中的动词是不是可接复合宾语，而且是不是被动语态，与此同时还要看其后部分的逻辑主语是不是句子的主语。
2. 另一种最简单的方法是:如果还不能看出来就可以把全句改成主动语态，加上一个主语we或people等。改成主动语态后，看后面是不是变成了"宾语+宾语补足语"了，这样我们就可以判别原句后面是不是主语补足语。例如:
被动句:She was found reading in the library. (主语补足语)
主动句:We found her reading in the library. (宾语+宾语补足语)
被动语态
一、被动语态的用法:
1.一般现在时的被动语态构成:is / am / are +及物动词的过去分词
Our classroom is cleaned everyday.
I am asked to study hard.
Knives are used for cutting things.
2.一般过去时的被动语态构成:was / were +及物动词的过去分词
A new shop was built last year.
Dinosaur eggs were laid long long ago.
3.现在完成时的被动语态构成:has / have + been +及物动词的过去分词
This book has been translated into many languages.
Many man-made satellites have been sent up into space by many countries.
4.一般将来时的被动语态构成:will+ be +及物动词的过去分词
A new hospital will be built in our city.
Many more trees will be planted next year.
5. 含有情态动词的被动语态构成:情态动词+ be +及物动词的过去分词
Young trees must be watered often.
Your mistakes should be corrected right now.
The door may be locked inside.
Your homework can be handed in tomorrow.
6.现在进行时的被动语态构成:am / is / are + being +及物动词的过去分词
Uncle Wang is mending my bike now.→
My bike is being repaired by Tom now.
They are planting trees over there. →
Trees are being planted over there by them.
7.不定式的被动语态:to + be +及物动词的过去分词
There are two books to be read.
There are twenty more trees to be planted.
二、 怎样把主动语态改成被动语态?
把主动语态改为被动语态非常简单，可以遵循以下几个步骤:
1. 先找出谓语动词;
2. 再找出谓语动词后的宾语;
3. 把宾语用作被动语态中的主语;
4. 注意人称、时态和数的变化。
例:1. Bruce writes a letter every week. →A letter is written by Bruce every week.
2. Li Lei mended the broken bike this morning.→The broken bike was mended by Li Lei this morning.
3. He has written two novels so far.→Two novels have been written by him so far.
4. They will plant ten trees tomorrow.→Ten trees will be planted by them tomorrow.
5. Lucy is writing a letter now.→A letter is being written by Lucy now.
6. You must lock the door when you leave.→The door must be locked when you leave.
三、 使用被动语态应注意的几个问题:
1.不及物动词无被动语态。
What will happen in 100 years.
The dinosaurs disappeared about 65 million years ago.
2. 有些动词用主动形式表示被动意义。
This pen writes well.
This new book sells well.
3.感官动词或使役动词使用省略to的动词不定式，主动语态中不带to ，但变为被动语态时，须加上to 。
例:make somebody do something→somebody+ be +made to do something
see somebody do something→somebody +be +seen to do something
A girl saw my wallet drop when she passed by.→My wallet was seen to drop by a girl when she passed by.
The boss made the little boy do heavy work.→The little boy was made to do heavy work by the boss.
4. 如果是接双宾语的动词改为被动语态时，直接宾语(物)作主语，那么动词后要用介词，这个介词是由与其搭配的动词决定。
He gave me a book.→A book was given to me by him.
He showed me a ticket.→A ticket was shown to me by him.
My father bought me a new bike. →A new bike was bought for me by my father.
5. 一些动词短语用于被动语态时，动词短语应当看作一个整体，而不能丢掉其中的介词或副词。
We can't laugh at him. →He can't be laughed at by us.
He listens to the radio every day. →The radio is listened to by him every day.
The nurse is taking care of the sick man. →The sick man is being taken care of by the nurse.
补充说明
系动词连接了主语和补语。这种结构中的补语是说明主语性状的，所以称为主语补足语。系动词作为实义动词的一类，具有本身的意义，但是在起到桥梁作用的同时，有些系动词会保持本身具有的意义，有些意义则会减弱或消失。例如:
1. I tasted the soup. ( taste 为及物动词，意思为"品尝"。)
2. The soup tastes wonderful. (taste 为系动词，意思为"尝起来，吃起来"，意思基本未变。)
3. He went to the cinema yesterday evening. ( go 是不及物动词，意思为"去，走"。)
4. At the news, he went mad. (go为系动词，失去了"go"的原义，意为"变得"。)
另外，英语中还有一定数量的不及物动词，完全保留了本身的词汇意义，同时又发挥着系动词的功能。它们与主语补足成分连用，所以这类词被称为"准系动词"(quasi-linking verb or half-linking verb)。用于"S+Vi+Cs"(S代表主语，Vi代表不及物动词，Cs代表主语补足语)这一句式的动词都属于这种用法。有时，主语补足语不紧跟系动词，有可能被其它状语成分隔开。以"go"为例:
5. At twenty-four, Tom went half-bald. ( go 为系动词，失去原义。)
6. After midnight, Tom went home bored.( go 为准系动词，保留原义，但同时又连接主语"Tom"和主补"bored"，"home"为副词，表示地点状语。)
用于这一句式的补语可以为各种形式，如名词词组(NP)，形容词词组(AP)，介词词组(Pr.P)，和分词短语(PP)等。现举例如下:
Type1: S + Vi +Cs (NP)
7. We parted the best friends.
= We were the best friends when we parted.
8. I stand before you today the representative of a family in grief.
= I am the representative of a family in grief when I stand before you today.
类似的动词包括: come (back), die, fall, go, leave 等。
Type2: S + Vi +Cs (AP)
9. They were born poor, lived poor, and poor they died.
= They were poor when they were born; they were poor when they lived; they were poor when they died.
10. She married young.
= She was young when she married.
11. The morning dawned fresh and clear after the storm at night.
= When the morning dawned after the storm at night, it was fresh and clear.
类似的动词包括:arrive, come (back), dawn, fall, leave, lie, marry, return, sit, stand, turn out 等。
Type3: S + Vi +Cs (Pr.P)
12. The parcel arrived in good condition.
= When the parcel arrived, it was in good condition.
13. They separated with feelings alienation.
= They had feelings alienation when they separated.
类似的动词包括:come, die, fall, go, leave, lie, part, return, sit, stand等。
Type4: S + Vi +Cs (P.P)
14. They stood listening to him.
= They stood while they were listening to him.
15. He came home convinced that she was telling the truth.
= He came home and he was convinced that she was telling the truth.
类似的动词包括:arrive, die, fall, go, leave, lie, return, sit 等。