fix grammar (#3769)

docs/patterns/fileuploads.rst

@@ -55,8 +55,8 @@ the file and redirects the user to the URL for the uploaded file::
                 flash('No file part')
                 return redirect(request.url)
             file = request.files['file']
-            # if user does not select file, browser also
-            # submit an empty part without filename
+            # If the user does not select a file, the browser submits an
+            # empty file without a filename.
             if file.filename == '':
                 flash('No selected file')
                 return redirect(request.url)
@@ -135,10 +135,10 @@ Improving Uploads
 .. versionadded:: 0.6
 
 So how exactly does Flask handle uploads?  Well it will store them in the
-webserver's memory if the files are reasonable small otherwise in a
+webserver's memory if the files are reasonably small, otherwise in a
 temporary location (as returned by :func:`tempfile.gettempdir`).  But how
 do you specify the maximum file size after which an upload is aborted?  By
-default Flask will happily accept file uploads to an unlimited amount of
+default Flask will happily accept file uploads with an unlimited amount of
 memory, but you can limit that by setting the ``MAX_CONTENT_LENGTH``
 config key::
 
@@ -167,10 +167,9 @@ Upload Progress Bars
 
 A while ago many developers had the idea to read the incoming file in
 small chunks and store the upload progress in the database to be able to
-poll the progress with JavaScript from the client.  Long story short: the
-client asks the server every 5 seconds how much it has transmitted
-already.  Do you realize the irony?  The client is asking for something it
-should already know.
+poll the progress with JavaScript from the client. The client asks the
+server every 5 seconds how much it has transmitted, but this is
+something it should already know.
 
 An Easier Solution
 ------------------