简述主犯的种类及其刑事责任处罚原则。
参考答案：
After the summer vacation, the professor, together with his fellow teachers, ______ the scientific experiment
A．goes down
B．go down
C．gets down to
D．get down to
贤袭人娇嗔箴宝玉 俏平儿软语救贾琏
