A:what
B:how
C:which
D:that
The ship was ____ (lock) in the ice during the whole winter.
1950年,中央人民政府颁布了有关土地改革的( )
体积相同的两物体a、b,如图所示,都浸没在水中,则两物体受到水对它们向上和向下的压力差的关系是( )