A sentence consists of a string of characters terminated by one of a set
 of single character delimiters.  The default sentence delimiters are:
 period (.), question mark (?), and exclamation point (!).  A sentence
 delimiter is considered to be a delimiter only if it is at the end of a
 line or if it is followed by a space.  The line terminator or trailing
 spaces are considered a part of the sentence.  There are three sentence
 entities:

     SEN   Specifies the entire sentence in which the cursor is positioned,
           including the delimiter and trailing spaces or line terminator.
     BSEN  Specifies all characters preceding the cursor in the current
           sentence.
     ESEN  Specifies all characters in the current sentence from the cursor
           to (but not including) the delimiter character.

 The sentence delimiters can be changed by the SET ENTITY command.