1. sometimes: on some occasions, but not always

例：

Sometimes I drive to work and sometimes I walk. （我有时开车去上班，有时走路去上班。）

Traffic noise is sometimes a problem. （交通噪声有时让人很难受。）

The journey takes about an hour, sometimes even longer. （行程大约一小时，有时会更久一些。）

Injuries of this type sometimes take a long time to heal. （有的情况下，这种创伤很久才能痊愈。）

2. occasionally: use this to talk about something that only happens a few times, and does not happen often

例：

Occasionally we go out to restaurants, but mostly we eat at home. （我们有时下馆子，但大部分时候都在家吃。）

very occasionally (=not at all often)

He lives in Australia now, so we only see him very occasionally. （他现在住在澳大利亚，我们偶尔才能见他一面。）

3. every so often: at fairly regular periods but not often

例：

Every so often, Frank looked up at me and smiled. （有时他会抬头看我冲我笑笑。）

The silence was broken every so often by the sound of guns in the distance. （宁静有时会被远方传来的枪声打破。）

4. once in a while: sometimes but not at all often

例：

It would be nice if we could see each other once in a while. （我们要是偶尔能见见面就好了。）

I do get a little anxious once in a while. （我有时会有点焦虑。）

Teaching art can be fairly dull, but once in a while I come across a talent that really excites me. （教艺术非常无聊，但是有时会碰上天才学生，这让我很兴奋。）

every once in a while (=fairly rarely)

Every once in a while he disappears for days on end. （偶尔他会一连消失几天。）

I saw her in the shop every once in a while. （我偶尔会在商店碰到她。）

5. at times: if something happens at times , it happens on particular occasions but it is not normal or typical of what usually happens

例：

In a job like this, you're bound to feel a little stressed at times. （做这种工作，难免有时会觉得有点压力。）

At times even the most talented athletes lose their motivation. （即使是天才运动员有时也会丧失动力。）

6. now and again/now and then: use this to talk about something that sometimes happens that is different from what happens most of the time

例：

I wear hats now and again, but they don't really suit me. （我有时会戴帽子，但我不适合戴帽。）

Now and then she would check on the baby sleeping in the next room. （她有时会到隔壁房间看看孩子睡得好不好。）

7. from time to time: sometimes, but not at all regularly and not very often

例：

This is the kind of problem that we all have from time to time. （这种问题，我们偶尔都会碰到。）

From time to time a helicopter flew by, but mostly the sky remained clear. （有时天上有直升机飞过，大部分时候天空都万里无云。）

8. off and on/on and off: for short periods, but not continuously or regularly, over a long period of time

备注：''off and on/on and off''常用于口语中。

例：

We've been going out together for five years, off and on. （这五年间，我们时不时会出去约会。）

I worked in bars on and off for two years before I decided to go back to college. （我时不时在酒吧上班，就这样过了两年后，我决定重返校园。）