“胸前推”是指立掌,臂由()部向前推。
A.背
B.肩
C.颈
参考答案:B
热原
An unstable upright equilibrium position on a vessel means that the metacenter is().
A.lower than the center of gravity
B.at the same height as the center of gravity
C.higher than the baseline
D.on the longitudinal centerline