Which classes in Futian Shangsha Middle School are the key classes?

Class one, class two, class three and class four. According to official website's inquiry, Shenzhen Futian Shangsha Middle School is a full-time public middle school founded by Futian District Government in 2005. There are three grades and 28 classes in junior high school, among which 1, 2, 3 and 4 classes are the key classes. Key classes need to pass the exam ranking and get excellent results before they can enter.