Joe Chen,
If you are going to quote on something you need more than opinions on an internet forum.
ASK THE COMPANY WHO SUPPLIED YOU WITH THE DRAWING.
I see similar questions to yours everyday when the poster seems to not want to seem unprofessional by asking the client for clarification.
I have worked as the Clients Quality Rep for many years and I would be very upset if a contractor went on an internet forum to ask for clarification rather than asking me,
Regards,
Shane