How grammar changes

If you think that grammar is an exact science, get ready for a shock. Grammar is a science, all right – but it is most inexact. There are no inflexible laws, no absolutely hard and fast rules, no unchanging principles. Correctness varies with the times and depends much more on geography, on social class, adn on collective human caprice than on the restrictions found in textbooks.
In mathematics, which is an exact science, five and five make ten the country over – in the North, in the South, in the West; in Los Angeles and Coral Gables and New York. There are no two opinions on the matter – we are dealing, so far as we know, with a universal and indisputable fact.
In grammar, however, since the facts are highly susceptible to change, we have to keep an eye peeled for trends. What are educated people saying these days? Which expressions are generally used and accepted on educated levels, which others are more or less restricted to the less educated levels of speech? The answers to these questions indicate the trend of usage in the United States, and id such trends come in conflict with academic rules, then the rules are no longer of any great importance.
Grammar follws the speech habits of the majority of educated people – not the other way around. That is the important point to keep in mind.
The following notes on current trends in modern usage are intended to help you come to a decision about certain controversial expressions. As you read each sentence, pay particular attention to the italicized word or words. Does the usage square with your own language pattrens? Would you be willing to phrase your thoughts in just such terms? Decide whether the sentence is right or wrong, then compare your conclusion with the opinions given following the test.

语法如何变化
如果您认为语法是一门精确的科学，请准备震惊。语法是一门科学，没错-但这是最不精确的。没有僵化的法律，没有绝对严格的规则，没有不变的原则。正确性会随着时代的变化而变化，它更多地取决于地理，社会阶级，集体的人为因素，而不是教科书中的限制。
在数学上，这是一门精确的科学，其中有五分之五的数学使全国占据了十个席位。在洛杉矶，科勒尔盖布尔斯和纽约。关于此事，没有任何两种意见-就我们所知，我们正在处理一个普遍而无可争辩的事实。
但是，在语法上，由于事实极易发生变化，因此我们必须时刻注意趋势。这些天受过教育的人怎么说？哪些表达通常在受过教育的水平上使用和接受，哪些其他表达或多或少地受到教育程度较低的语音的限制？这些问题的答案表明了美国的使用趋势，并且这种趋势与学术规则相冲突，因此这些规则不再具有任何重要意义。
语法使大多数受过良好教育的人的言语习惯无法实现-并非相反。这是要记住的重要点。
以下有关现代用法当前趋势的说明旨在帮助您决定某些有争议的表达方式。阅读每个句子时，请特别注意斜体字。用法是否与您自己的语言习惯相符？您愿意用这样的话表达您的想法吗？确定句子是对还是错，然后将您的结论与测试后给出的意见进行比较。