Studying abroad, I have to go back to China to see a doctor because of my physical problems. Does the school need to issue a certificate for returning to China for security inspection? Please don't.

China citizens who have gone abroad (traveling, studying abroad, doing business, etc.). ) and you don't need a visa to return to China halfway.

For China students studying in the United States, visas are documents issued by the United States, and they need to be checked during their entry and stay in the United States. If the student's visa is a one-time entry, the visa will automatically expire after leaving the United States for home. If you want to study in the United States, you need to apply for a new visa. There is no need to re-apply for multiple-entry visas within the validity period.

If you need to stay in the United States beyond the validity period of your visa for any reason, such as extending your study time, you should apply to the local immigration office for an extension before the expiration date to avoid the invalidation of your visa. It is illegal to use an expired visa. Once it is found out, it will bring you a bad record.