Concentrating on more than one thing?

Do you find it easy to concentrate on more than one thing at a time or can you only give one thing your full concentration?

For example while you are posting on GF do you only concentrate on posting on GF or could you do work/uni work or watch TV/listen to music/speak to people at the same time?

its depend what i am doing if i do work on some serious matter i would keep my whole concentration on that work. however, if i do some thing like that as i am posting right now i like to listen music and chat with friends. actually, i am a multitask-er. lol

I multitask. That's one reason I get to post and read GF and still have my house as it should be. But if I really want to concentrate on one thing, I can do that too (and be able to shut off all the other things around me no matter how they try to distract).