When to use "the"

     [This is a fast-access FAQ excerpt.]
This is often quite tricky for those learning English.  The
basic rules can be found in the Purdue University Online Writing
Lab's WWW page titled "The Use and Non-Use of Articles" [...]
     ["The Use and Non-Use of Articles" can now be found at
     <http://owl.english.purdue.edu/handouts/esl/eslart.html>.]
(very brief), and in "An Overview of English Article Usage for
Speakers of English as a Second Language" by John R. Kohl of
Rensselaer Polytechnic Institute [...]
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(As explained in the document "Accessing the Internet by E-Mail FAQ"
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     [This should now read 
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     as the message body.'] 
  The book Three Little Words; A, An and The: a
Foreign Student's Guide to English by Elizabeth Claire (Delta,
1988, ISBN 0-937354-46-5) has been recommended.
   The article "the" before a noun generally indicates one specific
instance of the object named.  For example, "I went to the school"
refers to one school.  (The context should establish which school
is meant.)  Such examples have the same meaning in all English-
speaking countries.
   The construct <preposition><noun>, with no intervening article,
often refers to a state of being rather than to an instance
of the object named by the noun.  The set of commonly used
preposition-noun combinations varies from one dialect to another.
Some examples are:
   I went to bed = I retired for the night.  Even if I had the
      habit of sleeping on the floor, I would still say "I went
      to bed" and not "I went to floor".
   She is at university (U.K.) = She is in college (U.S.) = She
      is a student, enrolled in a particular type of tertiary
      institution.  This sentence does not imply that she is now
      physically present on the campus.
   He was taken to hospital (U.K.) = He was hospitalized.  (A
      U.S. speaker might say "to the hospital" even if there
      were several hospitals in the area.)