声相关计程仪的测量精度主要取决于相关延时,而与下列()无关。
A.水流速度
B.船速
C.声速
D.两接收换能器间距
参考答案:C
与毛周角化症不符的是()
A.常见于青少年
B.冬重夏轻
C.与毛孔一致的坚硬角化性丘疹
D.发病与维生素A缺乏有关
E.好发于上臂、股外侧和臀部
He has_______big family. His family________eating dinner now. [ ]
A. a; is
B. a; are
C. the; is
D. the; are