Removed duplicated words in in comments and docs.
diff --git a/Python/pystrtod.c b/Python/pystrtod.c
index 859af43..ae6ab9c 100644
--- a/Python/pystrtod.c
+++ b/Python/pystrtod.c
@@ -324,7 +324,7 @@
 
    On overflow (e.g., when trying to convert '1e500' on an IEEE 754 machine),
    if overflow_exception is NULL then +-Py_HUGE_VAL is returned, and no Python
-   exception is raised.  Otherwise, overflow_exception should point to a
+   exception is raised.  Otherwise, overflow_exception should point to
    a Python exception, this exception will be raised, -1.0 will be returned,
    and *endptr will point just past the end of the converted value.
 
diff --git a/Python/random.c b/Python/random.c
index 0776bfc..1e5776d 100644
--- a/Python/random.c
+++ b/Python/random.c
@@ -274,7 +274,7 @@
 }
 
 /* Fill buffer with size pseudo-random bytes from the operating system random
-   number generator (RNG). It is suitable for for most cryptographic purposes
+   number generator (RNG). It is suitable for most cryptographic purposes
    except long living private keys for asymmetric encryption.
 
    Return 0 on success, raise an exception and return -1 on error. */
diff --git a/Python/thread.c b/Python/thread.c
index dd333e8..c54670d 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -271,7 +271,7 @@
         if (p->id == id && p->key == key)
             goto Done;
         /* Sanity check.  These states should never happen but if
-         * they do we must abort.  Otherwise we'll end up spinning in
+         * they do we must abort.  Otherwise we'll end up spinning
          * in a tight loop with the lock held.  A similar check is done
          * in pystate.c tstate_delete_common().  */
         if (p == prev_p)