Thanks for reply...
I understand i can re-enter. I haven't left US in last 7 months. But what should I say, if visa officer ask me where do u work in Canada and why you are in US for so long. My actual intention in not work in Canada. I just want to visit my friends in US. I have read many post in this forum which says you can re-enter Canada with valid work permit but they all are working in Canada.