[David L.]

It is really hard for me to master English articles(a(an)/the).
Could anybody show me the simplest explanation for these devils?

Thank you.

For all future posters of threads:
Can you see how important it is to be as clear as possible when asking for help? Based on the information above, I've gone completely down the wrong track, back to basics with this post.
The query is, there seem to be exceptions when 'the' is used which I don't understand, such as :
We often go to the sea.
b.I usually play the guitar after breakfast.
c.The earth goes around the sun.


Then I wouldn't have spent half and hour for nothing formulating the earlier response!