I moved my old site(www.mysite.com) to another location(blog.mysite.com). To keep worked my old URLs in Google, I added some codes in .htaccess like this:
the codes that I added work properly. But this time, when I do this, CS-CART SEO URLs fail, they don't work. So, I cannot delete them. I don't know what to do.
How can I add my extra codes in the .htaccess file?
So you want to move your store from 'www.yoursite.com' to a subdomain, 'shop.yoursite.com'. I'm really not sure with the .htaccess rules you have posted, unless you have changed your category URL structure and how you 'moved' the store, a much more simple .htaccess rule could be applied.
Did you just change the store paths in the config.local.php, or did you physically move the entire CS-Cart installation to a subdomain folder?
The following should do it, it sounds like you're placing your incorrect custom rules above the CS-Cart rules in your .htaccess file which is causing the CS-Cart specific rules to fall over.
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.yoursite\.com$ [NC]
RewriteRule ^(.*)$ http://subdomain.yoursite.com/$1 [R=301,L]