Introduction

Many people consider learning grammar a chore. And at times, it can be. But understanding the grammar of any language is essential for becoming a skilled and accurate user of that language. English is certainly  no exception.
The rules of grammar for a language learner are like the rules of the road for a driver. In order to be able to drive properly and maneuver with other drivers, you have to know the rules that everyone goes by.  Naturally, some people break the rules and make driving difficult for other drivers. This is true of language, too. If you follow the rules of grammar, you can express yourself clearly. But if you fail to observe those  rules, people may find it difficult to understand you or they may even misunderstand you entirely. So it’s really very important to understand and use correct grammar.
But what is grammar? Funk and Wagnalls’s New College Standard Dictionary describes grammar as “a type of science that explains the various principles of oral or written usage of a particular language.” It is also  said to be “the developed art of speaking or writing accurately in a particular language.” Whether science or art, grammar is made up of the descriptions that tell you how to use a language correctly. For example:
Description: Begin a sentence with do to change a statement to a question.
Usage: Statement = “You understand the problem.”
Question = “Do you understand the problem?”

Or:
Description: Use he as the subject of a sentence; use him as the direct object.
Usage: Subject = “He is a good friend of mine.”
Direct Object = “I visit him very often.”

There are many such grammatical descriptions, and each one is a building block in the structure of your knowledge of how to form and use English correctly. The greater the number of building blocks that you  master, the greater your accuracy with the spoken and written language will be.
Standard grammar is composed of the traditional rules for English. It is what grammarians and English professors want everyone to use when they speak and write. But a language evolves over time, and the  traditional rules sometimes seem out of step with what is going on in the English speaking world. The more current or popular usages can be called casual language. That’s what people really say in their everyday  lives and is often in direct contradiction with standard grammar. As an illustration, in standard grammar you should use who as the subject of a sentence and use whom when it is used as an object. But that’s not  always the case in casual language. For example:
Standard grammar: “Whom did you visit in New York?”
Casual language: “Who did you visit in New York?”

Although the first example is considered better grammatically, the second example sentence is the most commonly used.

Another kind of example involves the verb to dive. Its past tense is either regular (dived) or irregular (dove). What is the difference? Essentially, none. Both forms are used correctly as the past tense. But English is  evolving. Things are changing. And the English-speaking world is deciding whether it wants the past tense of the verb to dive to be regular or irregular. It may take quite a while longer to learn what that decision will  be. So for the time being you’ll continue to hear both dived and dove in the past tense.
There is a similar case with the verb to prove. Nowadays, many people use proved as the participle in a perfect tense: “He has proved” or “We had not proved.” But there are others who still use the archaic form  (proven), which today is generally accepted as an adjective, in place of proved:
“He has proven” or “We had not proven.”
The point here is that grammar rules will guide you toward speaking and writing better English.But many rules of grammar are broken by certain casual or popular usages and still others become unclear because  the language is in a state of transition. Where these deviations occur,they will be discussed in this book, because if English learners only know that who should be used as a subject of a sentence, they will be  confused by what occurs in casual language: “Who did you visit in New York?”
However, just knowing the rules of grammar is not enough. This book will also provide you with abundant practice in using English grammar. The more you practice, the more you become proficient in how you use  English and to what extent you understand it. There are various kinds of exercises to allow you to manipulate the language from different angles. The Answer Key at the end of the book gives you not only the right  answers but also suggestions as to how an exerciseshould be completed.
English grammar isn’t necessarily a chore. Indeed, it can be your key to unlocking a very rich treasure.