在寒假是on winter holiday还是in winter holiday

在寒假是on winter holiday还是in winter holiday in winter holiday还是on winter holiday 是in my winter holiday 还是 on my winter holiday.还是其他介词 是用in my winter holiday还是on my winter holiday? winter holiday 是winter and summer holiday 还是 winter and summer holidays? may day in winter holiday 为什么是winter holidays 而不是winter holiday 在假期是in the holiday 还是on the holiday? 到底是on holiday还是in holiday in winter 还是 on winter 是on holiday 还是at holiday 或in holiday