At last, the recent development of ultrasonic backscatter imaging is reviewed.最后, 简要介绍了超声背向散射成像的新进展.Officials at the Transportation Administration say they have already tried out a handful of backscatter scanners.运输安全局的官...

knockbacks的音标：...

backspace的第三人称单数（三单）为：backspaces...

backshaft的音标：backshaft的英式发音音标为：[bæk'ʃeɪft]backshaft的美式发音音标为：[bæk'ʃeɪft]...

backstep的音标：backstep的英式发音音标为：['bækstep]backstep的美式发音音标为：['bækstep]...

backsword的音标：backsword的英式发音音标为：['bæksɔ:d]backsword的美式发音音标为：['bæksɔd]...

反虹吸...

He made a quick drop , slanting down on his backswept wings, and then circled again.它倏地斜着后掠的双翅俯冲, 然后又盘旋起来....

adj.间接的...