To echo each other; to act in perfect harmony or concert (can be used neutrally or imply collusion).
在小组项目中，小李提出大胆的设想，小王则详细补充了实施方案，两人一唱一和，让整个计划变得可行且富有创意。
In the group project, Xiao Li proposed a bold idea, and Xiao Wang elaborated on the implementation plan. The two worked in perfect concert, making the whole plan feasible and creative.
Next Idiom