User-agent:Yandex
Disallow: /cat_1.html

Disallow: /cat_3.html
Disallow: /cat_4.html
Disallow: /cat_5.html

User-agent:*
Disallow: /cat_1.html

Disallow: /cat_3.html
Disallow: /cat_4.html
Disallow: /cat_5.html

User-agent: Yandex
Host: www.merker.ru