Conjunctions are words which join phrases, clauses and sentences.
Conjunctions have three basic forms which are shown in the table below.
|Single Word||and, but, because, although, or, etc.||Do you want chips or cake.|
|Compound||provided that, as long as, in order that/to, etc.||You need to exercise in order to lose weight.|
|Correlative||both/and, either/or, neither/nor, not/but, not only/but also||Either Monday or Tuesday is fine.
Not only should you eat fruit, but also vegetables.
Conjunctions also have two functions, as shown below.
|Coordinating conjunctions||Join equal (independent) parts of a sentence.||Always come between the words/clauses that they join.||Jack and Jill went up the hill.
The water was warm, but I didn't go swimming.
|Subordinating conjunctions||Join subordinate clauses to main clauses.||Usually come at the beginning of subordinate clauses.||I went swimming although it was cold.|
Although some people say it's not correct to use conjunctions at the beginning of a sentences, many famous writers do so.
Conjunction for Kids. Kiddle Encyclopedia.