是in summer还是on summer

是in summer还是on summer 请问是in summer vacation还是on summer vacation? 在夏天是用in summer 还是on summer 在暑假是on summer还是in summer还是at summer 是at the summer 还是 in the summer 还是on the summer 是in summer 还是in the summer 是in summer holiday还是on summer holiday有没有规律?总结一下! a hot summer day 前面用in还是on就是是用in a hot summer day还是on a hot summer day ( ) the summer holiday 填in还是on In a happy summer还是on a happy summer the summer 前加on还是in还是at at summer 还是IN SUMMER 在my summer vacation前面有on还是in. 英语翻译best wishes for you on the hot summer 还是in the hot summer? Many girls in our school like to ______skirts in summer.空格是填 wear 还是 put on 还是in 还是take in summer holiday or on summer holiday 这里的介词用in还是on?this summer vacation 前面的介词用in还是on?主要是限制summer还是vacation?还有像August of this year之类的, 是on summer holidays还是in summer holidays?我是这样理解的,一般有day的前面介词都是on,如：on Monday……希望权威人士给予正确解释