某一材料或物质的品目也包括由该材料或物质与其他材料或物质构成的混合物或结合物。
参考答案：对
With a lot of difficult problems________，the newlyelected president is having a hard time.[ ]
A．settled
B．settling
C．to settle
D．being settled
噪声级相减的公式为（）
A．A
B．B
C．C
D．D
