1. restrictions on use: single buildings are used for specific purposes, such as government office buildings, educational institutions and medical institutions. These buildings will not be sold, because the government or relevant institutions need to protect their right to use in specific fields in order to perform their duties and missions.

2. Return on investment: The single building does not have commercial value, or its value is inconsistent with the buyer's investment expectation. For example, the location where the single building is located is not prosperous enough, and the rent or sales income is low, which cannot guarantee the return on investment of the buyer.