句子的完整性是其基本要求。在英语的句子中，有些动词除一个宾语外，句意还不完整，必须加上宾语补足语才能将句意表达完整，因此宾语补足语是许多句子不可缺少的一部分，是句子的主要成分。这样的句型为：主语+谓语动词+宾语+宾语补足语。
常用的及物动词有：think，make，have，get,consider，find，call，let等。如：They found the room cleaned by someone.
宾语补足语的几种类型：
1.名词作宾语补足语
We think him a bright boy.
They call her XiaoZhang.
2.形容词及短语作宾语补足语
I found the dog dead.
Exercise makes you healthy and strong.
3.不定式及其短语作宾语补足语
She often asks me to help her with her English.
注：在使役动词make，let，have及see，watch，notice，observe，hear，listen to，find，feel等动词后的宾语补足语可用不定式，但不定式不可加to。
Nobody heard him cry for help.
I often see the boys play basketball after school.
4.现在分词及其短语作宾语补足语
The teacher caught her cheating in the exam.
They often hear me practising speaking English.
5.过去分词及短语作宾语补足语
He raised his voice to make himself heard clearly.
When I went downstairs,I found my bike stolen.
6.as引出的宾语补足语
We consider her as a great writer.
We took English as a useful tool.
7.介词短语宾语补足语
Please make yourself at home.
The illness kept her in bed for a month.
8.副词作宾语补足语
Did you find them in?
She ordered them away.
9.从句作宾语补足语
We will soon make our school what your school is now.
注：当复合宾语中的宾语是不定式、动名词或宾语从句时， 往往把宾语放在它的补足语后，而用it作句子的形式宾语，放在宾语补足语之前。如：
I think it wrong to smoke in public.
I find it hard to learn English well.
She kept it secret that she hadn’t passed the exam.
