Minor grammar fixes in readme

Author: phil-davis

README.md

@@ -102,7 +102,7 @@ fclose($fh);
 ```
 
 **Note**: write() will truncate your file to 0bytes. You may open a writeable stream with append() which will point
-the cursor to the end of the file or create it if it does not exists yet. (append() is only compatible with libsmbclient-php)
+the cursor to the end of the file or create it if it does not exist yet. (append() is only compatible with libsmbclient-php)
 ```php
 $fh = $share->append('test.txt');
 fwrite($fh, 'bar');
@@ -141,7 +141,7 @@ Note, setting the protocol version is not supported with php-smbclient version 1
 
 The `smbclient` backend needs to get various information about the system it's running on to function
 such as the paths of various binaries or the system timezone.
-While the default logic for getting this information should work on most systems, it possible to customize this behaviour.
+While the default logic for getting this information should work on most systems, it is possible to customize this behaviour.
 
 In order to customize the integration you provide a custom implementation of `ITimezoneProvider` and/or `ISystem` and pass them as arguments to the `ServerFactory`.