it is better to go to shopping malls, professional markets and office buildings of enterprises and institutions by credit card. Going into a shopping mall or a professional market is a bit like sweeping the street, and it is not very difficult. However, the office buildings of gold enterprises and institutions are blocked by the front desk and the doorman, and there is also access control, which is quite difficult. The simpler way is to buy a yellow page and then make a stranger visit according to the unit and address on the yellow page.