How dirty your room is! You must          .[ ]

A. clean up it        

B. clean them up    

C. clean it up        

D. do some cleanings

口腔颌面部常见的临界瘤是（）

A.根尖周囊肿

B.角化囊肿

C.始基囊肿

D.含牙囊肿

E.血管外渗性囊肿