12个频度副词

频度副词always(总是),usually(通常),frequently（经常） often （经常）sometimes(有时),seldom(不常),rarely（极少）,never（从不） once(一次),twice(两次),等.

频度副词在句中习惯上位于系动词、助动词、情态动词之后，行为动词之前。

1、在系动词之后。如She is sometimes very busy. 她有时很忙。

2、在第一个助动词或情态动词之后。如I will never forget this lesson. 我将永远忘不了这一课。

3、在实义动词之前。如We often go there. 我们常去那儿。

4、sometimes也可放在句首、句中或句末，often也可放在句末（一般不放在句首）。如Sometimes she writes to me. =She writes to me sometimes. 她有时候给我写信。She writes to me often. 她经常给我写信。

5、如果有两个助动词，频度副词通常放在第一个助动词后面。如We have never been invited to one of their parties. 他们聚会，一次也没邀请过我们。She must sometimes have wanted to run away. 她有时候一定想到过要逃走。