In English, we use two types of words to connect clauses. These are conjunctions and relative pronouns. Conjunctions are of two types: coordinating conjunctions and subordinating conjunctions.
Subordinate clause
A subordinate clause is a type of clause that cannot stand alone. Subordinate clauses are introduced by subordinating conjunctions. Examples are: as, because, since, when, while, if, whether, unless, that etc.
- I will give you a call when I am ready.
- As she was not ready, we went without her.
- Since they have apologized, we will not take any further actions against them.
A subordinate clause can come either at the beginning or at the end of a sentence. When subordinate clauses come at the beginning of a sentence, we usually separate them with a comma.
Main clause
A main clause is a type of clause that can stand alone. Main clauses are also called coordinate clauses. Main clauses are introduced by coordinating conjunctions like and, but, or, yet, so, for and nor.
- She is my friend and I like her.
- She was tired but she was cheerful.
- He is one of the best cricketers in the city, yet his favorite game is soccer.
- I like him so I helped him.
Relative pronouns
Relative pronouns are words like who, whom, whose, that and which. They are used to introduce relative clauses. Note that relative clauses are also called adjective clauses.
Relative pronouns connect two clauses. They also act as the subject or object of the verb in the relative clause.
- This is the girl who won the first prize.
- This is the problem whose solution has baffled everybody.
Relative adverbs
Relative adverbs are words like when, where and why. Like relative pronouns, relative adverbs are also used to connect two clauses.
- Do you know a place where I can buy used cameras?
- Do you know the reason why she hates me?
- I will never remember the day when I first met her.
