通气改善率测定中提示气道阻塞中度可逆的标准是（）。
A.10%
B.>15%
C.15%～24%
D.25%～40%
E.>40%
参考答案：D
I wanted some string but there was _____ in the house.[ ]
A. nothing
B. none
C. no one
D. not one
胆囊内可移动、无声影的病变可能是（）①泥沙样小结石②胆泥③出血④寄生虫
A.①
B.①②
C.①②③
D.④
E.以上均可能
