以下属于音频文件的是（）
A、sounD.doc
B、sounD.txt
C、sounD.bmp
D、sounD.wav
参考答案：D
Many working women ________ relatives to help take care of their children.
A．depend with
B．depend to
C．rely in
D．rely on
．水总是从高处流向低处是因为水受_____的作用，推桌子很难推动，是因为桌子受到_____的作用．
