Xiàkè hòu, xuéshēng men sānsānliǎngliǎng de huíjiā le.
After class, the students went home in twos and threes.
Tips
history
Traced to the Jin-dynasty poem 《娇女诗》 anthologized in Song poet 郭茂倩's《乐府诗集》: 鱼行不独自，三三两两俱 - fish don't swim alone, but travel in twos and threes. It has described scattered, casual groupings ever since.
usage
Almost always followed by 地 and a verb of movement (走，来，聚). Describes the pattern of a crowd - never a single group of 2-3 people.
