烃类热裂解中二次反应有()烯烃的聚合、环化和缩合、烯烃的加氢和脱氢、烃分解生成碳。
参考答案:烯烃的裂解
_____ is clear to us all, students should obey the school's rules. [ ]
A. As
B. What
C. Which
D. It
不属于足阳明经主治病的是()
A.侧头病
B.口齿病
C.咽喉病
D.热病
E.眼病