showing happiness or enjoyment

Her eyes sparkled merrily. 她的眼睛里闪烁着快乐的光芒。

without thinking about the result of what you are doing or about the problems it might cause

The factory has been merrily pumping chemical waste into the river for the past ten years. 过去10年里这家工厂一直在毫无顾忌地向河中排放化学废物。