从颜色不同的5个球中任取4个球放入3个不同的盒子中，要求每个盒子不空，则不同的放法总数为 ．（用数字作答）
180
把下面的六个图形分为两类，使每一类图形都有各自的共同特征或规律，分类正确的一项是（）
A.
B.
C.
D.
Which nursing action is most effective in defusing a client's impending violent behavior
A．Helping the client identify and express feelings of anxiety and anger.
B．Involving the client in a quiet activity to divert attention.
C．Leaving the client alone until he can talk about his feelings.
D．Placing the client in seclusion.
