그래 = To agree with a statement 왜 그래 = Why are you like this?

Here, http://www.koreanwikiproject.com/wiki/index.php?title=A/V_%2B_%EA%B2%A0%EB%8B%A4

못해 is a short and easy way of saying 할 수 없어.

It means, " Please look for healing. "

It means ' Thank you. ' The others like what mike jun has stated also share the same meaning.

You usually use 뭐지(informal/casual) or 뭐에요(informal/polite)

Ian W.'s examples are right. But for better explanation, 지금 = Right now 이제 = Now (shows that something has started (now) and it's effects will continue in to the future)

Rubby's answer is right. And there is also one more method. ~는중이에요 Eg, 먹는중이에요 = Eating/In the middle of eating This is used when you're doing it at that exact moment.