bpo-33649: A copy-editing pass on asyncio documentation (GH-9376)

diff --git a/Doc/library/asyncio-policy.rst b/Doc/library/asyncio-policy.rst
index 61727d4..42f936d 100644
--- a/Doc/library/asyncio-policy.rst
+++ b/Doc/library/asyncio-policy.rst
@@ -7,9 +7,9 @@
 Policies
 ========
 
-An event loop policy, a global per-process object, controls
-management of the event loop. Each event loop has a default
-policy, which can be changed and customized using the API.
+An event loop policy is a global per-process object that controls
+the management of the event loop. Each event loop has a default
+policy, which can be changed and customized using the policy API.
 
 A policy defines the notion of *context* and manages a
 separate event loop per context. The default policy
@@ -20,11 +20,11 @@
 :func:`new_event_loop` functions can be customized.
 
 Policy objects should implement the APIs defined
-in the abstract base class :class:`AbstractEventLoopPolicy`.
+in the :class:`AbstractEventLoopPolicy` abstract base class.
 
 
-Access the Policy
-=================
+Getting and Setting the Policy
+==============================
 
 The following functions can be used to get and set the policy
 for the current process:
@@ -111,14 +111,14 @@
 
 A process watcher allows customization of how an event loop monitors
 child processes on Unix. Specifically, the event loop needs to know
-when a child process has finished its execution.
+when a child process has exited.
 
 In asyncio, child processes are created with
 :func:`create_subprocess_exec` and :meth:`loop.subprocess_exec`
 functions.
 
-asyncio defines an abstract base class :class:`AbstractChildWatcher`
-that child watchers should implement, and has two different
+asyncio defines the :class:`AbstractChildWatcher` abstract base class,
+which child watchers should implement, and has two different
 implementations: :class:`SafeChildWatcher` (configured to be used
 by default) and :class:`FastChildWatcher`.
 
@@ -141,8 +141,7 @@
 .. note::
    Third-party event loops implementations might not support
    custom child watchers.  For such event loops, using
-   :func:`set_child_watcher` might have no effect or even can
-   be prohibited.
+   :func:`set_child_watcher` might be prohibited or have no effect.
 
 .. class:: AbstractChildWatcher
 
@@ -155,7 +154,7 @@
       another callback for the same process replaces the previous
       handler.
 
-      *callback* callable must be thread-safe.
+      The *callback* callable must be thread-safe.
 
    .. method:: remove_child_handler(pid)