辊式破碎机破碎时产生的粉尘（）。
A.较多
B.较少
C.一般
参考答案：B
The first question was difficult , but ___ were quite easy.
A．the second
B．the other
C．another
D．the rest
储蓄、股票、债券、商业保险等投资方式各有何特点？
