商品使用价值
参考答案：
是指商品满足人们和社会需要的效用，即有用性
The UN should﹍﹍the establishment of Iraqi government after the war, I think.
A．take part in
B．play a leading role in
C．play a role among
D．play a important part for
简述地铁防排烟系统的运作模式
