>    www.example.com/topics and
> www.example.com/articles
> to be mirrored.

The easiest way is through Options / Scan Rules:
-* +www.example.com/topics* +www.example.com/articles*

You may also use something like (to catch associated resources):
-* +www.example.com/topics* +www.example.com/articles* +www.example.com/*.gif
+www.example.com/*.jpg +www.example.com/*.css +www.example.com/*.js
+www.example.com/*.png