They make threats but back down at the first sniff of trouble.
他們起先氣勢洶洶，但一看情形不妙立刻軟了下來。
I'll take you back down to the valley.
我會帶你返回下面的`山谷裡。
His determination and refusal to back down had won the day
他的堅定和拒不退讓使他贏得了勝利。
It's too late to back down now
現在打退堂鼓已經太晚了。
I drove back down the highway at normal speed
我以正常車速沿公路返回。