(1) move backward ::
向后移动(2) backward compatibility ::
向后兼容性(3) forward and backward ::
向前和向后(4) walk backward ::
向后走(5) backward integration ::
后向一体化(6) go backward ::
留后路(7) backward-looking ::
保守的(8) backward and forward ::
向后和向前(9) backward glance ::
回头看一眼(10) backward motion ::
反向运动