He, she, it, they - Pronouns

Why pronouns are important 
Without pronouns we would have to repeat a word everytime we refer to the same thing or concept. Compare these two paragraphs to see the effect:

Pronouns are used as substitutes for other words and pronouns are very important to avoid repetition. Without pronouns texts often sound clumsy, as the texts need to use the same words over and over again. Pronouns can link texts without interrupting the flow of the texts as pronouns maintain the link to the same idea without using the same words.

Pronouns are used as substitutes for other words and are very important to avoid repetition. Without them texts often sounds clumsy, as they need to use the same words over and over again. Pronouns can link texts without interrupting their flow as they maintain the link to the same idea without using the same words.

Why is it important to use pronouns correctly? 
Incorrect use can be extremely confusing: changing from ‘he’ to ‘she’ suggests that the speaker no longer refers to a man but to a woman, going from ‘it’ to ‘they’ gives the impression that the object of conversation has just multiplied. Try one the exercises to test your use of pronouns or go to one of the links that explain how they are used.

Explanations and Exercises

A quick reminder of the differences between ‘she’ and ‘he’, ‘they’ and ‘it’ and the right use of ‘it’. 
http://owl.english.purdue.edu/handouts/grammar/g_pronuse.html

A comprehensive list of pronouns used in English.
http://esl.about.com/cs/beginner/f/f_pronouns.htm

The BBC Ask about English series explains why ‘it’ is different from ‘this’ and ‘that’. 
http://www.bbc.co.uk/worldservice/learningenglish/grammar/learnit/learnitv137.shtml

A quiz that asks you to find the words pronouns refer to. 
http://admn.santafe.cc.fl.us/~jgraney/reading/pronounref.htm

More exercises on pronouns. 
http://www.englisch-hilfen.de/en/exercises/pronomen.htm