如图所示，是超声波的何种伪像（）。
A.镜面效应
B.振铃效应
C.旁瓣效应
D.部分容积效应
E.声影
参考答案：A
--David will never ____ though he fails again and again.
--_______. So I believe both of you will succeed one day.
A．give up, Neither will you
B．give off, Neither you will
C．take up, So will you
D．take off, So you will
汽轮机油乳化的原因哪些？
