语言是交际的工具，为了达到更好的交际目的，人们 根据情景和交际的目的选择不同的文体。正式语言和非正式语言的运用是交际中重要的文体形式。在英语中正式英语用于比较严厉的场合，而非正式的英语用于比较随便的场合。下面是一些正式英语和非正式英语的形式。
1. 状语

1) 时间，原因和条件状语可以用非谓语动词的形式，也可以用状语从句的形式，一般的说，非谓语动词形式比状语从句形式正式。
Being (As he was) a farmer, he had to get up early.
Weather permitting (If weather permits), we shall go.
2)方式和程度状语可用介词短语，也可以用副词表示，一般说，介词短语比副词正式。
He spoke in a confident way/with confidence. (confidently)
3) 英语中用一些副词有两种形式，一种是-ly形式，一种是同形容词的形式相同，一般说，前者比后者正式。
He read loudly (loud).
I guessed rightly (right).
4) 让步状语从句 `how (who, when, what) ever‘ 的形式比 no matter how (who, when, what) 的形式正式。
Whoever (No matter who) he is, I wont‘ see him.

2. 代词
I. 关系代词
1) 定语从句中作宾语的关系词`Whom‘ 比 `who‘正式。 Whom (Who) are you waiting for?
He is the person whom (who) I met the other day.
2) 在定语从句中作主语和宾语的关系词`Who‘ `whom‘ and `which‘比 `that‘ 正式。
He is the person who (that) is well-known here.
This is the book which (that) I bought yesterday.
I know the person whom (that) you spoke to.
3) 指时间和地点的从句 `Prep + which‘ 比 `when‘ and `where‘ 从句正式。 This is the place in which (where ) I worked.
That is the day on which (when) I came.

II. 人称代词
1) 通常在比较级中主格比宾格正式。 He is taller than I (me).
Who is there ? It is I.(me)
2) 在动名词前，所属格比主格正式。 Do you mind my (me) smoking?
3) 单数人称代词比复数正式。
Everyone should do his (their) duty.
Give me (us) a kiss, darling.
Everyone thinks he knows (they know) the answer.
4) 指作者本人用 `We‘ 比 `I‘ 正式。 As we (I) showed it is not an easy question.
5) 泛指人时，`One‘ 比 `you‘ 正式。 One (You) never knows what may happen.
6) 在复合句中，主句和从句中的主语出现名词和代词时，主句中用名词比用人称代词正式。 The plane took off as soon as it had refuelled.
(It took off as soon as the plane had refuelled.)

III. 指示代词
1) 当`This‘ 和 `that‘都是后指时，‘that‘ 比 `this‘ 正式。 That (This) is what I thought.
2) `that/those‘ 作为先行词比名词正式。 Those flowers are better than those which (the flowers) we planted last year.

3. 主谓一致
1) 单数比复数正式。 None /Neither of them has (have) arrived yet.
2) 复数比单数正式。 If I were (was) you I would do that.
Neither his wife nor his child have (has) arrived.
There are (is) hundreds of people outside.
3) 和kind 连用的名词单数比复数正式。 This kind of dog (These kinds of dogs are) is easy to train.
I like most kind of cat (cats).
4. 倒装句比不倒装句正式。
Had I known it (If I had known it) I would have told you.
Hardly have I seen this. (I have hardly seen this.)
Under no circumstances must the door be left unlocked.
(The door must be left unlocked under no circumstances.)
Most of the problems a computer could solve easily.
(A computer could solve most of the problems easily.)

5. 不省略的形式比省略的形式正式。
I know that he is a famous writer.
He is a person whom I have known for several years.
I spent all the week in writing my paper.
I saw her on the day after her birthday.
We are going to visit China in the following spring.
You can borrow my pen if you want to borrow.
He suggested that we should come early.

6. 介词前提比介词结尾的句子正式。
He is a person on whom we can rely (whom we can rely on).
With what did he write it? (What did he write it with?)

7. 情态动词
1) 用于请求时，`May‘ 比 `can‘ 正式。 May (Can) I use your bike?
2) 用于请求时，`Would‘ 和 `Could‘ 比 `will‘ 和 `can‘ 正式。 Would /Could ( Will/Can) you like to give a speech?

8. 泛指时定冠词比名词复数正式。
The horse is a very useful animal.
(Horses are very useful animals.)

9. 从句比不定式的形式正式。
It is important that we should do it (for us to do it).
It seems that he is a teacher. (He seems to be a teacher.)

10. 其它的一些句子。
1) If you come early, you will see him. (Come early and you will see him.)
2) I shall try and do it. (I shall try to do it.)
3) He is so young that he can not dress himself.
(He is too young to dress himself.)
4) It is so beautiful a city. (It is such a beautiful city.)
5) Haven‘t you heard the news? (Have you not heard the news?)
6) To my surprise, I hear the news. ( I‘m surprised to hear the news.)
7) We starts for Beijing tonight. (We are starting for Beijing tonight.)
8) To begin with, (First ) we must consider this thoroughly.
9) I go to see my old friend occasionally (now and then).
10) I am hence (therefore) unable to help you.
11) By the way, (Incidentally) do you know something about this?
12) I was ill therefore (so) I could not come.
13) He spoke loudly in order that (so that) every one could hear him.