whenever指的是“在任何一个不具体的时间”。
比较
并列连词
when
I was walking along the street when suddenly someone patted me on the shoulder from behind.
我正在街上走着，这时忽然有人从后面拍我的肩膀。
when意为“这时”或“在那个时候”,可以看作是并列句,这种用法的when分句一般位于句末。
No sooner had we got to the station than the train left.
我们刚到车站，火车就走了。
Hardly had we begun when we were told to stop.
我们刚开始就被叫停。
The moment I heard the song, I felt cheerful.
= We shall go there tomorrow if it doesn’t rain.
Solong as you work hard, you will succeed.只要努力，你就会成功。
只要你努力工作，你就一定能成功。
In case I forget, please remind me about it .
语
从
句
so that
in order that
lest = for fear that
I shall write down your telephone numbersothat I may not forget.
我要把你的电话号码记下来，以免忘记。
We’ll tell you the truth so that you can judge for yourself.
你可以随意到你喜欢的任何地方去。
Wherever you go, you must obey the law.
无论你去哪都要遵守法律。
where与wherever意义基本相同，但后者语气较强，多用于书面语。
原
因
状
语
从
句
because
I came back late yesterday because I was on duty.
方
式
状
语
从
句
as
as if
as though
Draw a cat as I taught youyesterday.
按照我昨天教你的画只猫。
Do as you are toldto.
按照人家告诉你做的去做。
She looks as if she is ill.
看上去她好像是生病了。
He acted as if (though) nothing had happened.
并列连词for
As he didn’t know much English, he looked up the word in the dictionary .
由于他英语懂得不多，他在字典中查阅这个单词。
It must have rained last night, for the ground isstillwet.昨天一定下过雨，地还湿呢。
状
语
从
句
when
whenever
When I came into the room, he was writing a letter.
当我进屋时，他正在写信。
We shall go there whenever we are free.
我们什么时间有空，我们就去那里。
when指的是“某一具体的时间”。
as/so long as
in case
so/asfar as
Difficulties are nothing if we are not afraid of them.
如果我们不怕困难，困难就算不了什么了。
We shall go there to除非下雨，否则我们明天就去那里。
比赛开始后，他到了。
till
until
We waited till (until)he came back .
我们一直等到他回来。
She didn’t stop working until eleven o’clock .
她到11点钟才停止工作。
Until he had passed out of sight, she stood there.
directly,
instantly
As soon as I arrive in Shanghai, I’ll write to you.我一到上海就给你写信。I had hardly got home when it began to rain.
我刚一到家，就下雨了。=Hardly had I got home when it began to rain.
我把真实情况告诉你，以便你能自己做出判断。
They worked harder than usual in order that they could finish the work ahead of time.
他们比往常更加努力工作，为了能提前完成工作。
Put on more clothes lest (= for fear that ) youshouldcatch cold.
自从1978年以来中国发生了巨大的变化。
主句动词应为持续性的，从句动词为瞬间的。
状语从句在主句之前时一般用逗号与主句分开，如从句在主句之后则不必用标点符号。
as soon as
hardly…when
no sooner…than
the moment,
the instant,
the second,
immediately,
so…that
We turned up the radio, so that everyone heard the news.
我们把收音机的音量放大，结果大家都听到了新闻。
He was so excited that he couldn’t say a word.
他十分激动，以致一句话都说不出来。
so that前有逗号为结果状语从句。
昨天我回来晚了，因为我值班。
because用来回答why的问题，语气最强一般放在主句之后
since
Since everyone is here, let’s begin our meeting.
既然大家都到了，我们开始开会。
since表示既然或全已知的理由,稍加分析即可表明的原因,多放句首
as
比较：
Seeing (that) he was badly ill, we sent for the doctor.
鉴于他病情严重，我们派人去请医生去了。
consideringthat,seeing (that), now that和since意义相似，都有“鉴于某个事实”的意思，that可以省去。
目
的
状
while
While it was raining, they went out.
天下雨的时候，他们出去了。
I stayed while he was away.
他不在的时候我在。
All of us are working hardwhilehe is sleeping.(然而：并列连词)
while指“在某一段时间里”，“在…期间”，while引导的动作必须是持续性的。
我一听到这首歌，就感到很愉快
hardly…when和no sooner…than的意义相当于as soon as,但只表示过去发生的事情，主句为过去完成时，从句为过去时，如hardly或no sooner位于句首时语气强，而且主句的谓语要用部分倒装。
every time,
each time
last time
状语从句
状语从句是副词性从句，它在句子中担任状语，修饰主句的动词、形容词、副词或句子。根据修饰的方面，状语从句可以分为以下九种。
1、时间状语从句2、地点状语从句3、原因状语从句
4、目的状语从句5、结果状语从句6、条件状语从句
7、方式状语从句8、让步状语从句9、比较状语从句
种类
从属连词
例 句
说 明
时
间
地
点
状
语
从
句
where
wherever
Where there is a will, there is a way.
有志者，事竟成。
Where there is water there is life.
哪里有水，哪里就有生命。
You are free to go wherever youwant to.
他的行动就好像什么也没有发生。
They treat the black boy as if (though) he were an animal.
他们对待这黑孩子仿佛他是一头牲口。
此处as译为，按照或正如
as if或as though的意义和用法基本一样。从句中可以用现在时表示可能符合事实，也可以用虚拟语气。
从句常放在句首，说明次要的原因，主句说明结果，常用于口语中。
for连接的是并列句。
now that,
seeing that，
considering that,
Now (that) the weather has cleared up, we can start our journey.
鉴于天气已经晴朗，我们可以启程了。
It is so interesting a novel that all of us want to read it.