固体可燃物火灾场所应选用水炮系统。（）
参考答案：错
虎将；勇将( )
A．活动；运动
B．工人：农民
C．杏树；梨树
D．蛇行：爬行
It is useful to be able to predict the extent _____ a price change will affect supply and demand.
A．fromwhich
B．withwhich
C．towhich
D．for which
