Conjunction

Conjunction is a word that connects words, phrases, clauses or sentences. e.g.  and, but, or, nor, for, yet, so, although, because, since, unless, when, while, where are some conjunctions.
Examples.

     She tried but did not succeed.
     He does not go to school because he is ill.
     John and Marry went to the cinema.
     He thought for a moment and kicked the ball.
     I waited for him but he didn’t come.
     You will be ill unless you quit smoking.
     We didn’t go to the market because it was raining outside.

Single word Conjunction: Conjunction having one word
          e.g. and, but, yet, because etc.

Compound Conjunction: Conjunction having two or more words
       e.g. as long as, as far as, as well as, in order that, even if, so that etc

Types of Conjunction.

Conjunction is a word that connects words, phrases, clauses or sentences. e.g.  and, but, or, nor, for, yet, so, although, because, since, unless, when, while, where etc.

There are three types of conjunctions

1.  Coordinating Conjunction
2.  Subordinate Conjunction
3.  Correlative Conjunction

                                 Coordinating Conjunction.

Coordinating conjunctions (called coordinators) join
words, phrases (which are similar in importance and grammatical
structure) or independent clauses.

Coordinating conjunctions are short words i.e. and, but, or, nor, for, so, yet.

Coordination conjunction joins two equal parts of a sentence,

Examples.

     Word + word: She likes tea and coffee.
     Phrase + phrase: He may be in the room or on the roof.
     Clauses + clause: What you eat and what you drink affect your health.
     Independent clause + independent clause: The cat jumped over the mouse and the mouse ran away.

In the following examples, coordinating conjunctions join two words of same importance.

      She likes pizza and cake.               (pizza and cake)
      I bought a table and a chair.          (table and chair)
      He may come by bus or car.           (bus or car)

In the following examples, conjunction joins two independent clauses. Independent clause is a clause which can stand alone as a sentence and have complete thought on its own.

      I called him but he didn’t pick up the phone.
      I advised him to quit smoking, but he didn’t act upon my advice.
      He became ill, so he thought he should go to a doctor.
      He shouted for help, but no body helped her.
      He wants to become a doctor, so he is studying Biology.

Coordinating conjunctions always come between the
words or clauses that they join. A comma is used with conjunction if
the clauses are long or not well balanced. 

If both clauses have same subjects, the subject of 2nd clause may not be written again. See the following examples

     She worked hard and succeeded.
     The player stopped and kicked the ball.
     He became ill but didn’t go to doctor.
     Marry opened the book and started to study.

Subordinating conjunctions (called subordinators) join subordinate clause (dependent clause) to main clause.

e.g. although, because, if, before, how,  once,
since, till, until, when, where, whether, while, after,  no matter how,
provided that, as soon as, even if,

      MAIN CLAUSE + SUBORDINATE CLAUSE
      SUBORDINATE CLAUSE + MAIN CLAUSE

Subordinate clause is combination of
words (subject and verb) which cannot stand alone as a complete
sentence. Subordinate clause is also called dependent clause because it
is dependent on main clause. Subordinate clause usually starts with
relative pronoun (which, who, that, whom etc).  Subordinate clause
gives more information in relation to main clause to complete the
thought.

Subordinating conjunction joins subordinate clause to
main clause. Subordinating conjunction always come before the
subordinate clause, no matter the subordinate clause is before main
clause or after the main clause. 

Examples.
      He does not go to school because he is ill.
      I will call you after I reach my home.
      I bought some cookies while I was coming from my office.
      They played football although it was raining.
      Although it was raining, they played foot ball.
      As far as I know, this exam is very difficult.
      I have gone to every concert since I have lived in New York.
      You can get high grades in exam provided that you work hard for it.

                              Correlative Conjunction.

These are paired conjunctions which join words, phrases or clauses which have reciprocal or complementary relationship.

The most commonly used correlative conjunctions are as follows

     Either … or
     Neither … nor
     Whether … or
     Both … and
     Not only … but also 

Examples.

      Neither John nor Marry passed the exam.
      Give me either a cup or a glass.
      Both red and yellow are attractive colours.
      I like neither tea nor coffee.
      He will be either in the room or in the hall.
      John can speak not only English but also French