winter morning还是winter's morning?

winter morning还是winter's morning? 请问是In a cold winter morning 还是 on a cold winter morning? in the morning,on a winter morning 是on a cold winter morning还是in? 填空：__(介词) a cold winter morning. 是winter's day还是winter day I was born----a cold winter morning.It's----Dcember 12th.A.i early morning on new year's day和one night in the winter,这两句话 ———the morning of 2009 和____a winter afternoon 是填 on 还是in , The accident happened ______ a cold winter morning. The car accident happened( )a cold winter morning.填介词 he was born ()a very cold morning ()winter