胸廓前后径与横径之比为1:1，肋间隙增宽，应考虑为 ( )
A．气胸 B．扁平胸 C．漏斗胸 D．桶状胸E．鸡胸
参考答案：D
This photo reminds me _________ the days when I worked _________ the farm with my classmates.
A．about, in
B．of, on
C．about, on
D．of, in
简单链形悬挂第一吊弦点到定位点的距离为（）。
A.2m
B.4m
C.6m
D.8.5
