—Is your ball on the chair?
—No. It's ______ the chair. [ ]
A. on
B. in
C. under
D. at
答案:C
对数字测图方法,每平方公里图根点的密度,对于1:500比例尺的测图不少于( )个。
A.50 B.64 C.100 D.150
其诊断首先考虑
A.多根多处肋骨骨折B.血胸C.血心包D.开放性气胸E.张力性气胸