1. You can’t end a sentence with a preposition不能以介词结尾
(she enjoys being fussed over.她喜欢被簇拥的感觉)
(they must be convinced of the commitment that they are taking on.他们必须明确自己要承担的责任。)
(Tom had no-one to play with.没有人可以和汤姆一起玩)
Who、where、what打头的问句：questions beginning with who, where, what, etc.
(what music are you interested in?你喜欢什么样的音乐？)
2. You can’t start a sentence with a conjunction不能以连词开头
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.
3. Double negatives are always ungrammatical双重否定不符合语法规则
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 one, so that it means ‘I have something for you.’
当两个否定词汇一同使用时，这种用法是不符合语法规则的。原因是两个否定实际上互相抵消，表达肯定的含义。例如，这句话“I don’t have nothing for you”不符合语法，因为严格意义上来讲这两个否定词汇在一起表达了肯定的含义，表示“我有东西给你”。
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.
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.
I couldn’t not help him. [meaning: I strongly felt I should help him]
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.
对外行人来说，分裂不定式是在to和之后的动词之间放置一个副词，如“to lightly tap(轻拍)”。分裂不定式对语法爱好者而言是个常见的让人苦恼的问题。但是有很多著名的英文散文家喜欢使用分裂不定式的写作方式。不过，要小心使用分裂不定式，仍然有文体书和专家认为这是文体错误。
She used to secretly admire him.
You have to really watch him.
Those who believe that split infinitives are grammatically incorrect would rewrite these sentences as:
She used secretly to admire him.
You really have to watch him.
5. You can’t start a sentence with hopefully hopefully不能作为句子开头
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 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和其他句子副词不同，可以使用‘it is hopeful that’ 或者‘it is thankful that’的结构
Hopefully, planning delays will be minimal.
It is hopeful that planning delays will be minimal.
It is to be hoped that planning delays will be minimal.