1. You can’t end a sentence with a preposition 不能以介詞結尾

一般情況因該避免以介詞結尾。但以下四種情況用介詞結尾卻更自然。

被動結構：passive structures

 (she enjoys being fussed over.她喜歡被簇擁的感覺)

條件從句：relative clauses

 (they must be convinced of the commitment that they are taking>不定式結構infinitive structures

 (Tom had no-one to play with.沒有人可以和湯姆一起玩)

Who、where、what打頭的問句：questions beginning with who, where, what, etc.

(what music are you interested in?你喜歡什么樣的音樂？)

2. You can’t start a sentence with a conjunction 不能以連詞開頭

Conjunctions are words such as and, but, so, and if, which are used to connect clauses, sentences, or words. This grammatical superstition arises from the thought that because these words are used to connect separate clauses.The argument against using and or but to introduce a sentence is that such a sentence expresses an incomplete thought (or ‘fragment’) and is therefore incorrect. However, this is a stylistic preference rather than a grammatical rule.

連詞包括and、but、so、if等詞語，用于連接從句、句子或單詞。人們認為這些詞是用來連接獨立的從句，所以才有了這種錯誤觀點。還有人認為使用and或者but來引出的句子表達的觀點使不完真給的，所以是不正確的。不過，這只是一個風格的偏好，而不是語法規則。

3. Double negatives are always ungrammatical 雙重否定不符合語法規則

When two negatives are used to communicate a negative, then the usage is ungrammatical. The reason for this is that two negatives actually cancel each other out and create an affirmative statement. For example, the sentence ‘I don’t have nothing for you’is ungrammatical because the presence of two negatives technically switches the meaning to an affirmative>

當兩個否定詞匯一同使用時，這種用法是不符合語法規則的。原因是兩個否定實際上互相抵消，表達肯定的含義。例如，這句話“I don’t have nothing for you”不符合語法，因為嚴格意義上來講這兩個否定詞匯在一起表達了肯定的含義，表示“我有東西給你”。

Even though the use of double negatives in formal speech and writing is nonstandard, the use of double negatives is common in areas such as informal speech and popular music.

即使在正式演講和寫作中使用雙重否定是不標準的，但在非正式的演講和流行音樂等領域雙重否定是很常用的。

However, there is one use of double negatives that is entirely grammatical. In this use, the double negative is used to express and reinforce an affirmative

然而，有一個雙重否定的使用是完全符合語法的。在使用雙重否定表達肯定或者加強肯定語氣的。

I couldn’t not help him. [meaning: I strongly felt I should help him]

我要幫助他。

4. Splitting infinitives is a mistake 不定式不能分隔使用

For the uninitiated, splitting infinitives is the practice of placing an adverb between ‘to’and the corresponding verb, as in ‘to lightly tap.’Splitting infinitives is a common peeve of grammar enthusiasts, but like many such peeves it has been employed by well-regarded English prose stylists for centuries. However, take care before splitting those infinitives; many style guides and professors would still consider this a stylistic error.

對外行人來說，分裂不定式是在to和之后的動詞之間放置一個副詞，如“to lightly tap（輕拍）”。分裂不定式對語法愛好者而言是個常見的讓人苦惱的問題。但是有很多著名的英文散文家喜歡使用分裂不定式的寫作方式。不過，要小心使用分裂不定式，仍然有文體書和專家認為這是文體錯誤。

例如：

She used to secretly admire him.
她曾經偷偷愛慕他。

You have to really watch him.
你必須真得看著他。

Those who believe that split infinitives are grammatically incorrect would rewrite these sentences as:

認為分裂不定式不符合語法規范的人會主張這樣改寫上面的句子：

She used secretly to admire him.
她曾經偷偷愛慕他。

You really have to watch him.
你必須真得看著他。

5. You can’t start a sentence with hopefully  hopefully不能作為句子開頭

This use of hopefully to mean ‘it is hoped’rather than the adverbial ‘in a hopeful manner’has been disputed in the past several years, though it has found its way into general acceptance.

hopefully這個詞的意思是“有希望地”，而不是狀語“以一種充滿希望的方式”。在過去的幾年里，這種用法雖然已經被普遍接受但一直有爭議的。

Hopefully and thankfully can’t be reworded along the lines of other sentence adverbs, using the constructions ‘it is hopeful that’or ‘it is thankful that’:

Hopefully 和thankfully和其他句子副詞不同，可以使用‘it is hopeful that’ 或者‘it is thankful that’的結構

Hopefully, planning delays will be minimal.

希望比賽盡可能不被推遲。

It is hopeful that planning delays will be minimal.

希望比賽盡可能不被推遲。

也可以這樣改寫：

It is to be hoped that planning delays will be minimal.

希望比賽盡可能不被推遲。

（來源：滬江英語）