“表语”和“宾语补足语”的概念是什么？怎么用？

表语（predicative)是用来说明主语的身份、特征和状态的。它的位置在连系动词（be,become,appear,look,seem等）之后。

可用作表语的词有：

He is careful.(是形容词作表语，千万别用副词carefully)

He is a boy.(名词)

He is in.（副词）
= He is at home.（介词短语）

This food tastes good.( 形容词good作表语，千万别用副词well)

That was what I said.(句子作表语，用的是表语从句)

It's me. (代词）

He is twelve.(数词）

To see is to believe.(（动词不定式)

Seeing is believing.（现在分词）

His watch is broken.(过去分词)

宾语补足语是补充说明宾语的成分
1、常接形容词作宾语补足语的动词有：keep, make, find等。如：We must keep our classroom clean.

2、常接名词作宾语补足语的动词有：call, name, make, think等。如：We call them mooncakes.

3、常接动词-ing形式作宾语补足语的动词有：see, watch, hear, find, keep等。如：In the country, we can hear birds singing.

4、常接介词短语作宾语补足语的动词有：keep, find, leave等。如：I left my pen on my desk at home.

5、常接带to的动词不定式作宾语补足语的动词有：ask, tell, want, teach, wish等；接不带to的动词不定式作宾语补足语的动词有：see, watch, hear,