位于鼻中线的无痛肿块,邻近皮肤常有凹痕,可能是
A.黏液囊肿
B.鼻咽囊肿
C.皮样囊删
D.根尖囊肿
E.黏膜下囊肿
参考答案:C
September 10th is __________ Day.
A.the Teacher’s
B.Teachers’
C.the Teachers’
D.Teacher’s
简述脱碳器的原理,其填料起什么作用?