on a cold night为什么要用介词on

on a cold night为什么要用介词on 为什么有时候用at night ,有时候用on a cold night night什么时候用介词on什么时候用at比如at night ,on school night,on a cold night ( ) a cold winter night.是用in还是on? the murder____(happen) on a cold night a cold night前的介词到底是用in还是at还是on?那为什么可以说in the evening? 时间前面什么时候+on/in具体时间+on,我知道,那什么时候+in?为什么是On a cold night?a cold night是一个不确定的时间吧,为什么用on呢?那如果没有定语cold，就是night用in还是On？ 为什么是on a cold night,in a sunny morning it is on a cold moring为什么用on It was a cold night when he was on duty They got there ___ a cold night.A.at B.in C.on D.for【告诉我为什么、】 英语介词问题on a cold night为什么是on a cold night 不是in a cold night 或者是at?是因为有cold这个形容词修饰night吗? He was born on a very cold night _A_ December A of B in c on答案为什么选A而不选B或C? on a cold winter day,还是in a cold cold winter day为什么不用in He arrived ( ) a small village ( ) a cold night.A.at;on B.in;on C.at;at D.in;at要原因 The poor man died ( )a cold winter night.A inB at C byD on This story happened on a cold winter in 2007.请问这里用on对不对,为什么? ____ a summer night 为什么要用on而不是in或at.