back and forth

US /bæk ən fɔːrθ/
UK /bæk ən fɔːrθ/
"back and forth" picture
1.

來回, 往返

moving first in one direction and then in the opposite direction repeatedly

:
The pendulum swung back and forth.
擺錘來回擺動。
They walked back and forth across the room.
他們來回走過房間。
2.

來回, 往返

between two points, people, or places

:
The ball went back and forth between the players.
球在球員之間來回傳遞。
They exchanged emails back and forth for days.
他們來回發送郵件好幾天。