Index: io.c
===================================================================
--- io.c	(revision 32137)
+++ io.c	(working copy)
@@ -5462,6 +5462,7 @@
  *  be passed <i>file</i> as an argument, and the File object will
  *  automatically be closed when the block terminates. In this instance,
  *  <code>File.open</code> returns the value of the block.
+ *  See <code>IO.new</code> for a list of values for the opt parameter.
  */
 
 /*
@@ -5476,6 +5477,7 @@
  *  be passed <i>io</i> as an argument, and the IO object will
  *  automatically be closed when the block terminates. In this instance,
  *  <code>IO.open</code> returns the value of the block.
+ *  See <code>IO.new</code> for a description of values for the opt parameter.
  *
  */
 
@@ -6432,8 +6434,8 @@
  *  - "fmode:extern:intern".
  *  <code>extern</code> is the external encoding name for the IO.
  *  <code>intern</code> is the internal encoding.
- *  <code>fmode</code> must be combination of the directives. See
- *  the description of class +IO+ for a description of the directives.
+ *  <code>fmode</code> must be a file open mode string. See
+ *  the description of class +IO+ for a description of mode string directives.
  *
  *  When the mode of original IO is read only, the mode cannot be changed to
  *  be writable.  Similarly, the mode cannot be changed from write only to
@@ -6569,7 +6571,7 @@
  *  These mode and permission bits are platform dependent;
  *  on Unix systems, see <code>open(2)</code> for details.
  *
- *  Optional _opt_ parameter is same as in <code.IO.open</code>.
+ *  Optional _opt_ parameter is same as in <code>IO.open</code>.
  *
  *  === Examples
  *