1:   What do these mean: C-h, M-C-a, RET, "ESC a", etc.?
  
  C-x means press the `x' key while holding down the Control key.  M-x means
  press the `x' key while holding down the Meta key.  M-C-x means press the
  `x' key while holding down both the Control key and the Meta key.  C-M-a
  is a synonym for M-C-a.  RET, LFD, DEL, ESC, and TAB respectively refer to
  pressing the Return, Linefeed (aka Newline), Delete, Escape, and Tab keys
  and are equivalent to C-m, C-j, C-?, C-[, and C-i.  SPC means press the
  Space bar.
  
  I put any key sequence that is longer than one key (and some single-key
  sequences) inside double quotes or on a line by itself.  Any real spaces
  in such a key sequence should be ignored; only SPC really means press the
  space key.
  
  The ASCII code sent by C-x (except for C-?) is the value that would be
  sent by pressing just `x' minus 96 (or 64 for uppercase `X') and will be
  from 0 to 31.  The ASCII code sent by M-x is the sum of 128 and the ASCII
  code that would be sent by pressing just the `x' key.  Essentially, the
  Control key turns off bits 5 and 6 and the Meta key turns on bit 7.
  
  For further information, see `Characters' and `Keys' in the online manual.
  
  NOTE: C-? (aka DEL) is ASCII code 127.  It is a misnomer to call C-? a
  "control" key, since 127 has both bits 5 and 6 turned ON.  Also, on very
  few keyboards does Control-? generate ASCII code 127.