Each article in my website has three different urls.Take an artilce of which id is 10909 for example, one url is 'print.asp?ThreadID=10909'，another is 'showpost.asp?ThreadID=10909'，the other is 'article.asp?ThreadID=10909' Some people told me that it is not good and advise me to block two urls and keep only one url. How to edit my robots.txt? Is it right to write as follows? Disallow:showpost.asp Disallowrint.asp I am not sure about that.Please give me your opinions and tips.