Every speaker of a language has, in his or her head, a set of rules for using that language. This is a grammar, and—at least in the case of one's native language—the vast majority of the information in it is not acquired by conscious study or instruction, but by observing other speakers; much of this work is done during infancy. Language learning later in life, of course, may involve a greater degree of explicit instruction. The term "grammar" can also be used to describe the rules that govern the linguistic behaviour of a group of speakers.

The term "English grammar," therefore, may have several meanings. It may refer to the whole of English grammar—that is, to the grammars of all the speakers of the language, which means including a great deal of variation. Alternatively, it may refer only to what is common to the grammars of all, or of the vast majority of, English speakers (such as subject-verb-object word order in simple declarative sentences). Or it may refer to the rules of a particular, relatively well defined variety of English (such as Standard English). "An English grammar" is a specific description, study or analysis of such rules. A reference book describing the grammar of a language is called a "reference grammar" or simply "a grammar". A fully explicit grammar exhaustively describing the grammatical constructions of a language is called a descriptive grammar. Linguistic description contrasts with linguistic prescription, which tries to enforce rules of how a language is to be used.

Parts of speech:

All the communication skills, consulting of listening, speaking, reading and writing, can be practiced only with words. The different types of words used in the sentence are called parts of speech. Basically, there are eight parts of speech they are the following:

Noun
Pronoun
Verb
Adjective
Adverb
Preposition
Conjunction
Interjection

The Noun

This part of speech is commonly called naming words. They name some persons, certain places, some quality, some things or material and some groups. Nouns are divided into five Kinds: Common nouns-: these noun refer to general names used commonly for places, persons etc.

Ex: women, bus, country, city, solider 

Proper nouns-: Names of particular places persons or things are called Proper nouns.

Ex: Abhilash, Madhuri, India, Hyderabad . 
Collective noun: When We Name groups, these names are called collective noun.

Ex: a crowd, a bunch, a class, mob etc 
Abstract nouns: These nouns indicate quality of a person, activity condition, state, ideas or names expressing emotional process etc...

Ex: Kindness, cruelty, punctuality, love, fear, generosity etc 

Materials nouns: these are names of materials or things out of which some other things or products are manufacture.
Ex: leather, wool, copper, silk, paper etc

The Pronoun

Words used instead of a noun are called pronouns. They are used to avoid the repetition of nouns and to make communication more pleasant.

Verb

The verb is an action word it is also a word that shows a state or condition. It also denotes possession.
Ex: Ravi killed a snake. (Action)
Radha is not well. (State)
Abhinav has a Maruthi car. (Possession)

Adjective

Adjectives are words that give more information about a noun or a pronoun. In other words, they describe a noun or a pronoun.
Ex: Delhi is beautiful city
                  Adjective  noun

Some adjectives have "ed" or "en" ending.
Ex: She is an educated lady
                        Adjective  noun
Articles

"Articles" play a vital role in English language. We do not have such a thing like "articles" in Indian languages. Therefore we have to learn the right usage articles, when to use them and where to omit them. Articles are divided into two groups:

•Indefinite article - "a", "an".

•Definite article - "The".

"Articles" are like adjectives.
Ex : - He is the man whom I met yesterday at the bus-stop. Here "the" (definite article) does the function of an Adjective. "The" refers to particular person.

Similarly, "a" and " an" are used as number Adjective.
Ex : - I took an umbrella and went out of the house.
Here "an" has the meaning of "one umbrella" showing the number.

The Adverb
Adverb has three important functions to perform in a sentence.

1. It modifies or tells more about has an action is done, when an action is done etc .
Ex: the old man Was walking slowly
                                Verb    Adverb
They came late
           Verb  Adverb
2. An Adverb also modifies on Adjective
Ex: She is a very Beautiful Girl .
                  Adverb Adjective
An adverb can also describe another adverb.
Ex : She speaks Quite clearly
                        Adverb Adverb

Preposition
Preposition show relationship between

a Verb and a Noun
a Verb and a Pronoun.
an Adjective and a Noun
one Noun and another Noun
Ex:They are sitting on a bench
                   Verb   prepo      noun
She stood by him in thick and their.
       Verb prepo pronoun
The woman was kind to Raju
                         Adj  Prepo Noun
The boys were playing in the playground
    Noun                               prepo    Noun
Note: Sometimes prepositions are placed at the end though most of the time they are placed between the Words they relate to
Ex: What are you searching for ?
Ex: Whom are you talking about ?

Conjunction

Conjunctions are words that join words or sentences.
Ex : - Sunita and Krishan are friends
He is poor but he is honest

Kinds of Conjunctions

Coordinating conjunctions - They join sentences of equal rank.
Ex: - Molly sang and Polly danced

Co-relative or pair conjunctions - They are used in pairs.
Ex: - Not only Raghu but also Rani came for the function.

Sub-Ordination Conjunctions - These conjunctions join clauses.
Ex : - I will come if you invite me.

Interjection

Interjection is the name given to words that express sudden feelings of joy, sorrow, surprise etc ...An exclamatory mark (!) is used after the Interjection. Sometimes a group of words express sudden feelings.
Some examples are given below : Bravo ! That was beautiful
                                Hurrah ! we have won the match.
                                Alas ! The poor man is no  more.
                                Oh ! What a beautiful  night.
                                Well done ! Arsha

Verb - Tenses

"Tenses" mean the time of action. When an action is performed in the present, it is called the present tense, Similarly if it is in the past, it is called the past tense and if it is the future it is called the future tense.

Every finite verb has three forms : V 1 - V 2 - V 3
Ex: Eat-ate-eaten
     v1  v2    v3

The Present Tense

Simple Present -  eats - (singular subject)
                          eat - (plural subject)
Present Continuous - is eating (singular subject)
                            -  are eating (plural subject)
Note : - With " I" we use "am eating"

Present perfect - has eaten (singular subject)
                      -  have eaten (plural subject)
Present perfect Continuous - has been eating (singular subject)
                                       - have been eating (plural subject)

The Past Tense

Simple past - ate (singular & plural subject)
Note : - V2 form as it is.

Past continues - was eating (singular subject)
               - were eating (plural subject)
Past perfect - had eaten (singular and plural subjects)

Past perfect continuous - had been eating (singular and plural subjects)

The Future Tense

Simple future - Shall/ will eat (common to singular and plural subject)

Future continuous - shall/ will be eating (common to singular and plural subject)

Future perfect - shall/ will have eaten (common to singular and plural subject)

Future perfect continuous - shall/ will have been eating (common to singular and plural subject)

Know the uses of tenses

Simple Present

To express habits, customs, universal truth.
Ex : - My father goes for morning walk everyday.
            The Muslims fast during the month of Ramzan
            The earth moves round the sun

To speak of planned or scheduled activities and while making request, giving orders and instructions.
Ex : - (a) All the schools in Andhra Pradesh re-open, after summer vacation, in the month Of June.
         (b) The Konark express leaves Secunderabad Railway Station at 11 o' clock in the

Present Continuous

To speak about actions going on at the time of speaking
Ex : - Don't disturb. They are studying.

To indicate near future.
Ex : - I am leaving for Chennai tomorrow.

To express things happening now-a-days

Infinite/ Gerund/ Participle

A finite verb has three forms i.e. V1 - V2 - V3 . with the help of these three parts we form different types of tenses.

An infinite cannot form tenses. It can be used with singular and plural subject and with any person (first, second or third person) without any change

Active and Passive Voice

When subject of a sentence directly does an action, then the verb is said to be is the active voice.
Mr. Srinivas wrote this poem (Active voice)
         Subject  Verb           Object

A verb is said to be in the passive voice when it shows that something is done to the subject.
This poem was written by Mr. Srinivas . (Passive voice)

Concord

Concord or the agreement between the subject and the verb, in the both numbers and in persons, is one of the most problematic items in the function English. Many question based on this concept appear in the "sentence correction" section of CAT. Therefore it is better to have a through knowledge about "Concord".

Direct and indirect speech

Direct Speech
Direct speech points out the exact words of the persons speaking. while writing we place these words, within inverted commas or question marks.

Examples of direct speech:

1. she said , "I am eating now"
2. He said to the child, "do not disturb me"
3. Abhinav said to Radha, "where are you going?"

Indirect Speech
When we report someone's words to a third party, we do not use the exact words of the speaker. We make lot of changes while reporting. This is called indirect speech the above sentences can be reported as follows.

Examples of indirect speech or reported speech:

1.She said that she was eating them (Told)
2.He warned the child not to disturb him. (Commanded)
3.Abhinav asked Radha when she was going. (Enquired)

Idioms

Idioms are expressions which function as a single units and whose meaning cannot be worked out form its separate parts. "kick the bucket" is an example for the above statement. It is an idiom which means die. In cat a few wrongly used idioms may come for correction. The basic idea is that we cannot change the words of the idiom. For example "spread like wild fire" is an idiom which means to spread fast. Now you or I cannot change this idiom "spread like wild fire" into spread like forest fire' or "spread like fire in the wilderness" etc. ..........