> Use the HTTrack Website Copier 3.47.20 update ASP
> host, will just download the
> changed webpage.


Are you sure ? The server replies with "200" (OK code with new contents) when
updating, and unfortunately httrack can not "guess" that the pages haven't
actually changed.

[1] request for www.tmjzzx.com/news.asp?cat_id=36:
<<< GET /news.asp?cat_id=36 HTTP/1.1
<<< If-Modified-Since: Sat, 31 May 2014 12:20:22 GMT
<<< Cookie: $Version=1; ASPSESSIONIDASDDDDQT=PIGNMCHAFEEMAPGKMNLLFBAF;
$Path=/
<<< Connection: keep-alive
<<< Host: www.tmjzzx.com
<<< User-Agent: Mozilla/4.5 (compatible; HTTrack 3.0x; Windows 98)
<<< Accept:
text/html,image/png,image/jpeg,image/pjpeg,image/x-xbitmap,image/svg+xml,image/gif;q=0.9,*/*;q=0.1
<<< Accept-Language: en, *
<<< Accept-Encoding: gzip, identity;q=0.9

[1] response for www.tmjzzx.com/news.asp?cat_id=36:
code=200
>>> HTTP/1.1 200 OK
>>> Server: nginx/1.1.19
>>> Date: Sat, 31 May 2014 12:20:54 GMT
>>> Content-Type: text/html
>>> Transfer-Encoding: chunked
>>> Connection: keep-alive
>>> Cache-Control: private
>>> X-Powered-By: ASP.NET
>>> Content-Encoding: gzip