Open terminal, and keyed:
cd /etc
sudo vi hosts
and keyed password and then press Enter.
Then you need press “Blank” key to browse to the bottom part of the page.
Press “E” key, it means no matter what you would like to edit the file hosts.
In English input mode, press “i” to insert letter or character actions.
And use keys  ←↑→↓ to move to the bottom of the letter page.
I suggest you goto next line, add the contents below (copy and paste are all avaliable):
127.0.0.1 practivate.adobe.com3 Q! l, B) v  B5 b- ^/ U
127.0.0.1 www.adobeereg.com
127.0.0.1 activate.adobe.com
Press ESC, and type :wq (including the colon), press Enter then it’s done!