sentence  -- Operation, two inputs.  Abbreviation: se
     The two inputs may be words or lists.  The output  is  a  list  formed
     from  the two inputs in this way: if either input is a word, that word
     becomes a member of the output list; if either input is  a  list,  the
     members of that input become members of the output.  Here are some ex-
     amples:

          first input         second input        output
          "hello              "test               [hello test]
          "goodbye            [cruel world]       [goodbye cruel world]
          [a b]               [c d]               [a b c d]
          []                  "garply             [garply]

     If an input is the empty list, as in the last example above,  it  con-
     tributes nothing to the output.
