1ADV [ADVERB after verb]并排,并肩(行进) If people or things walk or move abreast, they are next to each other, side by side, and facing in the same direction. 并排,并肩(行进)
The steep pavement was too narrow for them to walk abreast.
陡坡太窄,他们没法并排走。
...a group of youths riding their motorbikes four abreast.