单项选择题
A.侧卧 B.仰卧 C.俯卧 D.视情况确定
A.30° B.60° C.90° D.视情况决定
A.5s B.10s C.15s D.20s
A.1s B.2s C.l~1.5s D.l~2s
微信扫一扫,加关注免费搜题