diff --git a/Doc/library/bdb.rst b/Doc/library/bdb.rst
index c0c3dc8..93304de 100644
--- a/Doc/library/bdb.rst
+++ b/Doc/library/bdb.rst
@@ -342,12 +342,10 @@
 .. function:: effective(file, line, frame)
 
    Determine if there is an effective (active) breakpoint at this line of code.
-   Return breakpoint number or 0 if none.
-
-   Called only if we know there is a breakpoint at this location.  Returns the
-   breakpoint that was triggered and a flag that indicates if it is ok to delete
-   a temporary breakpoint.
+   Return a tuple of the breakpoint and a boolean that indicates if it is ok
+   to delete a temporary breakpoint.  Return ``(None, None)`` if there is no
+   matching breakpoint.
 
 .. function:: set_trace()
 
-   Starts debugging with a :class:`Bdb` instance from caller's frame.
+   Start debugging with a :class:`Bdb` instance from caller's frame.
diff --git a/Doc/tutorial/stdlib.rst b/Doc/tutorial/stdlib.rst
index 955ce73..844f8bc 100644
--- a/Doc/tutorial/stdlib.rst
+++ b/Doc/tutorial/stdlib.rst
@@ -14,11 +14,11 @@
 operating system::
 
    >>> import os
-   >>> os.system('time 0:02')
-   0
    >>> os.getcwd()      # Return the current working directory
    'C:\\Python26'
-   >>> os.chdir('/server/accesslogs')
+   >>> os.chdir('/server/accesslogs')   # Change current working directory
+   >>> os.system('mkdir today')   # Run the command mkdir in the system shell
+   0
 
 Be sure to use the ``import os`` style instead of ``from os import *``.  This
 will keep :func:`os.open` from shadowing the built-in :func:`open` function which
diff --git a/Doc/whatsnew/2.7.rst b/Doc/whatsnew/2.7.rst
index 5ba22a7..6cd3aba 100644
--- a/Doc/whatsnew/2.7.rst
+++ b/Doc/whatsnew/2.7.rst
@@ -244,7 +244,7 @@
 modules.
 
 * The :mod:`ConfigParser` module uses them by default, meaning that
-  configuration files can now read, modified, and then written back
+  configuration files can now be read, modified, and then written back
   in their original order.
 
 * The :meth:`~collections.somenamedtuple._asdict()` method for