我们注意到操作词都是动词的现在式或过去式，是限定动词形式。限定动词形式可以并只可以用于谓语动词词组第一动词的位置。也就是说操作词在句子中的位置是谓语动词词组第一动词位置。

当一个句子按语法要求需要用操作词而原句没有操作词时，就在谓语动词词组第一动词位置加上助动词do的现在式或过去式，使其具有操作词。助动词do后接原实意动词的不带to的不定式形式。

操作词的语法特征如下：

1. 肯定句变否定句时否定词not直接置于操作词之后。

He will come tomorrow.

He will not come tomorrow.

He loved her.

He did not love her.

2. 非正式语体尤其口语中，操作词可以和not构成缩合式。（am的缩合式ain't只用于俚语）。缩合后为重读。注意正式语体不可用操作词和not的缩合式。

3. 参与一般疑问句和选择疑问句的构成：操作词移至主语前，句末用问号，读升调：

He is an English teacher.

Is he an English teacher (or math teacher)?

He wants to buy a car.

Does he want to buy a car (or a motorcycle)?

4. 反义问句（附尾问句）的问句部分构成：操作词 + 人称代词？（前否后肯，前肯后否）

You have two children, haven’t you？（英式）/don’t you?(美式)

He won’t come, will he?

5. 有的词项前置时（如否定副词或only加状语），需要部分倒装句，就是操作词的倒装：

   I have never seen this before.

   Never have I seen this before.

   He had scarcely finished his dinner when she came.

   Scarcely had he finished his dinner when she came.

   We had a meeting only when necessary.

   Only when necessary did we have a meeting.

   He gets up at six o’clock every day.

   When does he get up every day? (疑问词前置导致部分倒装。)

   Three students were late for class.

   How many students were late for class? (疑问词本身就位于主语前，并无前置，所以不倒装。)

（部分倒装句（即操作词的倒装）是由前置导致的结果，前置的内容是信息中心。

完全倒装句（实意动词的倒装）是后移带来的结果，信息中心在句末。）