是in vacation,还是on vacation,还是atvacation?

是in vacation,还是on vacation,还是atvacation? 请问是in summer vacation还是on summer vacation? 应该用in vacation还是on vacation vacation 前用什么介词?是in?还是on? 是travel to vacation,还是travel on vacation 是go on vacation 还是go on a vacation?是go for vacation还是go for a vacation? 我去年在北京度假用英语怎么说?是in vacation还是on vacaton? 到底是on holiday还是in holiday那是（ ）vacation，括号中填介词 in the vacation ；go on vacation ；on vacation 区别? vacation前的介词用on还是in? 在my summer vacation前面有on还是in. in vacation,on vacation的区别 in vacation和on vacation的差别 是on vacation还是on a vacation 它们有什么区别? 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, 到底是on their vacation 还是 for their vacation啊?求解! 请问“我们在山上度假”用英语怎么说?RT,是We are on a vacation in the mountain 还是We are on a vacation in the mountains?用不用复数? go on vacation还是go on a vacation?