The number of teachers in our school _____ greatly increased last term. A number of teachers in this

school _____ from the countryside.[ ]

A. was; is        

B. was; are    

C. were; are        

D. were; is

口腔黏膜出现白色斑块或白色网状条纹多由于（）

A.上皮表层过度角化

B.上皮萎缩

C.棘层松解

D.基底细胞液化变性

E.黏膜下层非特异性炎症