What does the 70-year property right in Shenzhen real estate transaction mean?

Houses in our country's cities are all built on state land, and state-owned land cannot be changed. People who buy a house only have property rights, not complete property rights, only land use rights. Now the policy life of the house is 70 years. After 70 years, the country will use land, and your property right expires, so you can only buy a house again. If the country doesn't need land after 70 years and your house is not in danger, you can go through the relevant procedures again. I hope I can help you.