Hi, I will be stopping in Shanghai (Pudong airport) for 4 hours when I fly from Hong Kong to Japan, and for 7 hours when I fly from Japan back to Hong Kong.

Will I have enough time to go out of the airport and see the Shanghai Expo? How long does it take to travel from Pudong airport to the nearest Expo entrance? I'm fine with seeing any pavilion, as long as there isn't a queue. Would I have to book this in advance?

Thanks!