step back
1．yield ground by moving to the rear；recede后退
He stepped back to admire the painting．他退了几步来欣赏这幅画。
We stepped back politely to let the ladies pass．我们礼貌地后退，让女士们过去。
2．move backwards from surprise，shock，etc．由于吃惊而后退
When he saw it，he stepped back in surprise．他一看到它，就吃惊得往后退。
She stepped back，hardly able to believe her ears．她吃惊地往后退缩，简直不能相信自己的耳朵。