It is an infringement of copyright to do any of the following acts in relation to a substantial part of a work protected by copyright without the consent or authorisation of the copyright owner:
Copy it issue copies of it to the public rent or lend it to the public perform or show it in public communicate it to the public.
As mentioned above, for infringement to take place it must involve a substantial part of the work.
Whether or not the part to be reproduced is substantial is subjective and the quality, importance or significance of the extract are equally as important (some may say more so) as the quantity of words or lines - using just four lines of a poem or even a four word extract have been found to be substantial.
The test is subjective. It is often said that if something is worth copying, it is worth protecting.
Secondary infringement may occur if someone, without the permission of the copyright owner, imports an infringing copy, possesses or deals with it or provides the means for making it.
Gold 4change - Lawyers Department