You want China, don't you? To apply for an American university, you need to have the ability of social practice, which is what you call extracurricular activities. There are many extracurricular activities, such as going to send warm and going to nursing homes. Don't write that it is organized, but that you personally thought of going to a nursing home to take care of your grandparents in special weather. Either you climb mountains boldly, or you take part in outdoor survival activities, and so on. These will do.

Social practice must be positive energy, and it is an activity that can reflect your positive, optimistic, healthy and kind side, so it is ok.