频度副词何时可位于助动词之前

.

频度副词何时可位于助动词之前
 
一、频度副词的概念与用法
频度副词是指表示动作发生的次数副词，常见有的never, seldom, sometimes, frequently, often, usually, always 等。频度副词通常位于实义动词之前，动词be、助动词、情态动词等之后。如：http://yingyu.chazidian.com
We often get together. 我们常常聚会。
Jane usually goes to work by bike. 简通常骑自行车上班。
He sometimes goes there on business. 他有时到那里出差。
He can never understand. 他永远也不会明白的。
I was never very good at maths. 我的数学从来不好。
I shall always remember this. 我将永远记住这一点。
You have often been told not to do that. 多次告诫过你别干那事。
注：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。
二、频度副词位于助动词之前两种情况
1. 为了表示强调，频度副词有时也可位于动词be、助动词、情态动词之前；此时助动词等应重读。如：
She always was late. 她老是迟到。
I never can remember. 我永远也记不住。
She hardly ever has met him. 她几乎从来没有遇见过他。
He never should have joined the army. 他根本不应当参军。
2. 在简略答语中，当频度副词与动词be、助动词或情态动词位于句末时，频度副词必须前置。如：
“Philip is late again.” “Yes, he always is.”“菲利普又迟到了。”“是的，他总是迟到。”
“Can you park your car near the shops?” “Yes. I usually can.” “你可以在商店附近停车吗?”“是的，通常可以。”
I know I should take exercise, but I never do. 我知道我应该进行体育锻炼，但我从来没这样做过。