题目

下面文章中有五处需要添加小标题。请从文后选项中选出符合各段意思的小标题。How often do you go on vacation? Everyone wants to have much fun on vacation. Here are some tips.【1】When you go on vacation, it’s important to do such a thing. You need to think about where to go, how to go there, what to do there, how much to spend and what to take with you. Also, you need to know what the weather will be like in the place you’re going to.【2】Sometimes going alone（单独地）is kind of boring. When someone else is around you, things will get more interesti设Sn为数列{an}的n前项和，an=2n-49，则Sn取最小值时，n的值为A.12B.13C.24D.25