Degrees of Comparison

The Comparative construction is used when we want to compare an object with another/some others. The common construction is by using adjective+er/est or more/most+adjective. But there are also some irregularities especially on some adjectives such as: good, bad, little and far. The comparative does not only use adjective but also use adverb. Of course it is used when an action of an agent is compared to the other action done by other agent.
The following link is useful for you to know more about Degrees of Comparison.

1. http://3nglish7.blogspot.com/2010/02/degrees-of-comparison.html
2. http://www.english-for-students.com/Degrees-of-Comparison.html
3. http://grammar.ccc.commnet.edu/grammar/adjectives.htm 
4. http://catatanbahasainggris.blogspot.com/2009/03/comparative-and-superlative-adverbs.html 
5. http://learningnerd.wordpress.com/2006/09/02/english-parts-of-speech-adjectives-determiners-and-adverbs/ 

and exercises:

1. http://www.learnenglish.be/gr2_degrees_study.htm 
2. http://www.learnenglish.be/gr2_degrees_ex2.htm 
3. http://www.learnenglish.be/gr2_degrees_ex3.htm 
4. http://www.learnenglish.be/gr2_degrees_ex4.htm 
5. http://www.learnenglish.be/gr2_degrees_ex5.htm 
6. http://www.better-english.com/grammar/comparatives.htm 
7. http://www.better-english.com/grammar/comp2.htm