Father's Day is _______ June 21 this year. [ ]
A. at
B. in
C. on
D. to
C
纤维化慢性下颌下腺炎的治疗方法是()。
A.硬化剂治疗
B.导管结扎术
C.药物治疗
D.摘除涎石
E.下颌下腺摘除
气溶胶包括()
A.粉尘、雾和烟
B.气体、烟和蒸气
C.气体、粉尘和烟
D.气体、蒸气和雾
E.蒸气、粉尘和烟