English Grammar Pronouns

Pronouns

A pronouns usually refers to something alredy mentioned in a sentences or piece of text. They are used instead of nouns to prevent repetition of the noun to which they refer. One of the most common pronouns is it.
Example (singular) :
Without a pronouns :
The train was late, the train had been delayed. (sounds horrid, doesn't it?)
With a pronoun :
The train was late, it had been delayed. (much better!)
In this example the train is singular, therefore the pronoun must be singular also - it.
Example (plural)
Without a pronoun :
The trains were late, the trains had been delayed. (still sounds horrid, doesn't it?)
With a pronoun :
The trains were late, they had been delayed. (much better!)
In this example the trains are plural, therefore the pronoun must be plural also - they.