企鹅为什么不能飞呢？大多数人坚持“鸟会飞”的观点，由此认为企鹅也会飞。但实际上，哪有这么绝对的判断标准呢？任何事情都有例外，英语学习中的语法法则也是如此。
英语语法可以分为规定性语法（prescriptive grammar）和描述性语法（descriptive grammar）。规定性语法即明确规定出什么正确、什么不正确，这有利于为学习者提供一个正确的语言范本，尤其是在其初级阶段。描述性语法则着重于描述和解释人们实际运用语言的方式，而不是规定语言应当如何使用。这两种语法体系是不一样的，而且后者还会随着时间而不断变化。基于此，将语法书视为权威的做法就同因为“鸟会飞”而坚持“企鹅也会飞”的看法一样荒谬。
对于大多数英语学习者来说，语法书更像是一本行为规范手册，指导我们正确使用英语。但大多数语法书籍都是对一种语言使用规则的概括与简化。为什么没有一本语法书来教我们所有这些“母语人士的语法”呢？因为描述性语法并非一成不变，世界上根本不存在一本能够涵括所有语言使用具体情景的语法书，没有人能够编写，也没有人能够全部掌握。
因此，在英语学习中，应以规定性语法为基础，但也必须不断学习了解描述性语法，避免让学习陷入僵化的教条主义。
本篇课程首发于2018年12月10日
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Grammar. Why Penguins Can't Fly
① For most students 'a grammar book' means a reference book which can be used when they are in doubt about an English sentence.
② The book will tell them whether a particular form is possible or not. Many possible English sentences will be excluded from that book. The book will, to some extent, artificially simplify the language. Why?
③ Native speakers learn most of their grammar system intuitively, without explicit training, when they acquire the language as children.
④ They instinctively know what can and can't be done with grammar. They don't study the rules.
⑤ It is not the case that the rule exists first, and the language must fit it. The truth is 'native speaker language' exists first, and the grammar book then attempts to describe it.
⑥ With this in mind any grammar structure which native speakers frequently produce can be called 'correct grammar'.
⑦ So why don't we have grammar books that teach us all this 'native-speaker grammar'? For a start it would be an enormous book and it would take a life-time to study it.
⑧ So the majority of grammar books present a simplified set of standard rules. Rules create a model that can be studied in a given time-frame. Students of English can never hope to fully learn anything approaching the whole of the language but they can study a simplified system.
⑨ This sometimes means they think certain sentences are not possible, when in fact they are quite natural English.
⑩ The rules in traditional grammar books give us lists of dos and don'ts and many of these rules are regularly violated by native speakers.
⑪ Taking the grammar book as the absolute authority is a bit like insisting that penguins should get up in the air because 'birds fly'.
▍生词好句
particular /pəˈtɪkjələ, pərˈtɪkjələr/: adj. 详细的；特别的
exclude /ɪkˈsklu:d/: vt. 排除；排斥
artificially /ˌɑ:.tɪˈfɪʃəl, ˌɑ:rt̬əˈfɪʃəl/: adv. 人工地；人为地；不自然地
intuitively /ɪnˈtʃu:ɪtɪvli/: adv. 直观地；直觉地
explicit /ɪkˈsplɪsɪt/: adj. 明确的；清楚的
time-frame /ˈtaɪm ˌfreɪm/: n. 时间范围
dos and don'ts: 行为准则
violate /ˈvaɪəleɪt/: vt. 违反；侵犯
authority /ɔ:ˈθɒrəti, əˈθɔːrət̬i/: n. 权威；权力
▍词汇拓展
1. The definition of "grammar" (Oxford English Dictionary):
· The whole system and structure of a language or of languages in general, usually taken as consisting of sentence structure and word structure and sometimes also sounds and meanings
· an analysis or study of the system and structure of how a language is used
· "a grammar", a book on grammar
· a set of strict rules about correct use of a language
2. Descriptive grammar / Prescriptive grammar
· Descriptive grammar is where you look at what native speakers do with their language and you record what native speakers do with grammar and then you see that as the "correct" grammar. In descriptive grammar, "people come first" and rules follow the people.
· Prescriptive grammar is where someone writes some rules and then tells everyone else that they have to speak like that. In prescriptive grammar, "the rules come first".
· An analysis or study of the system and structure of how a language is used (descriptive)
· A set of strict rules about correct use of a language (prescriptive)
3. I would dance.
我将会跳舞。（过去将来时）
I would be dancing.
我这会儿正在跳舞。（过去将来进行时）
I would have danced.
我本来会跳舞的。（过去将来完成时或虚拟语态）
4. Why the grammar book will artificially simplify the language?
The grammar book will tell you most of the important sentence structures that are useful for a learner of English. To do this, the grammar book must simplify the language–the grammar book looks at the most important building blocks of English and then it explains these building blocks of English one by one–it tells you how to put the words together, what those words mean when they are together and the situations where we can use that structure and the situations where you cannot use that structure.
5. intuitively: naturally, automatically, without thinking about it
Grammar is acquired through a subconscious process.
语法是在潜意识下获得的。
6. You don't need to know the name of all of different parts of a car to be a good driver.
成为一个好司机并不需要你将汽车所有不同的部件名称都熟记于心。
7. dos and don'ts: rules about how people should and should not behave
My new work place has lots of dos and don'ts; it's quite strict.
我新入职的公司有很多规章制度，非常严格。
8. the highest absolute / authority = expert
He is an authority on European art.
他是欧洲艺术领域的权威人士。
He is an expert on European art.
他是欧洲艺术领域的专家。
She is an authority on Italian wine.
她是意大利葡萄酒领域的权威人士。
She is an expert on Italian wine.
她是意大利葡萄酒领域的专家。
He is the absolute authority on European art.
他是欧洲艺术领域中绝对的权威人士。
He is the highest expert on European art.
他是欧洲艺术领域中最厉害的专家。
9. "Sometimes" rules are not rules.
10. Recommended grammar books:
· Michael Swan's "Practical English Usage"
· "Collins COBUILD English Grammar"
▍责任编辑
武志琳、李焕、章晓丹