定义：在英文中，用来表示动作频率的词被称为“频度副词”。
频度副词有：总是、通常、经常、常常、有时、偶尔、几乎、几乎不和几乎决不等。
频度副词在句中习惯上位于系动词、助动词和情态动词之后， 行为动词之前。
其中，系动词是用来辅助主语的动词，它本身有词义，但不能单独用作谓语，其后必须跟表语，构成系表结构，以说明主语的状况、性质和特征等情况。
频度副词有哪些
always
表示最频繁
often
次之
sometimes
有时候
频率最低
I
always
go
to
school
on
time.
我每天上学都不迟到
I
often
go
to
school
on
time.
我一般来说上学都不迟到
Sometimes
I
go
to
school
on
time.
我有时候上学不迟到
明白了？
英语频度副词有哪些?
频度副词（ Adverbs of Frequency ）表示动作发生或状态存在的频繁程度.这类副词（词组）中,有的所表示的频度很明确,例如：once,twice,three times a day,every week,every other day 等；有的所表示的频度比较含糊,例如：often,usually,always,sometimes,now and then 等.
1 ． Never(0) 从来都不,决不.该词位于句首时,句子的主谓语要倒装.例如：Never have I met such a strange man.（我从没见过这样奇怪的人.）
2 ． at no time (0) 从不,任何时候都不（ =not at any time ）.该词组置于句首时,句子的主谓语要倒装.例如：
At no time has he said such words.（他在任何时候都没有说过这种话.）
3 ． seldom/rarely(5%) 很少,难得.这两个词均有否定意思,置于句首时,句子的主谓语要倒装.例如：
My family seldom go to the movies.（我们家很少去看电影.）
Seldom/Rarely does she eat breakfast on workdays.（工作日期间她几乎不吃早餐.）
4 ． hardly ever (5%) 几乎不,难得（ =almost never ）.例如：
I hardly ever see her nowadays.（近来我很少见到她.）
5 ． once in a while (5%) 偶尔,有时,间或.例如：
I went to see him once in a while.（我偶尔去看他.）
6 ． from time to time (10%) 时常,有时.例如：
He dropped in on me from time to time.（他有时顺便来看我.）
7 ． sometimes (20%) 有时.例如：
On weekends sometimes we stay at home,and we visit our friends sometimes.（周末我们有时在家,有时去会朋友.）
8 ． at times (20%) 有时,偶尔.例如：
I do feel a little nervous at times.（我有时的确感到有点紧张.）
9 ． now and then (20%) 时而,不时.该词组前面有时可与 every 连用.例如：
He raised his eyes every now and then while reading.（他看书时不时地抬起头来歇歇眼睛.）
10 ． as often as not (50%) 往往.例如：
As often as not the buses are late on foggy days.( 每遇多雾天气,公交车往往晚点.)
11 ． more often than not (55%) 多半.例如：
More often than not they help us.（他们经常帮助我们.）
12 ． constantly (60%) 时常,不断地.例如：
The teacher is constantly asked for explanation of the text by his students.（学生们不断地要老师讲解课文.）
13 ． frequently (60-70%) 时常,频繁地.该词强调一段时间内动作发生的频繁程度.例如：
Advertisements appear frequently on the TV screens.（电视屏幕上广告频频出现.）
14 ． often (60-70%) 经常.强调习惯性,有时相当于 very frequently .其反义词为 seldom .例如：
My grandma often says,“I love books.They give me knowledge and make me happy.” （奶奶常说,“我喜欢书,书给我知识,使我快乐.”）
15 ． usually (80%) 通常.例如：
What time do you usually get up on Sundays?（你周日通常几点起床?）
16 ． almost always (90%) 几乎总是.例如：
Those who are almost always thinking of others should be the more,the better.（几乎总是为别人着想的人越多越好.）
17 ． always (100%) 总是.其反义词是 never .例如：
No matter what the weather is like,you can always find surfers out riding the waves.（无论天气怎样,你总是可以看到冲浪运动员外出冲浪.）
18 ． all the time (100%) 始终；一直；在全部时间内.例如：
Our knowledge of the universe is growing all the time.（人类对宇宙的认识一直在增加.）
