连接半挂车时，使牵引车的牵引座与挂车的牵引销连接后，将锁止杆置于哪个位置？
A．锁止
B．松开
C．紧固
D．断开
参考答案：A
We were all worried over _______ you were sick.
A．that
B．which
C．what
D．the fact that
民主集中制
