Our school is on Guangming Street. It's next to the People's Library. There is a park across from our school. The pay phone is between our school and a post office. Our school is very beautiful. There are many trees and flowers in it. If you want to come to our school from the airport, take a taxi and go down Center Avenue. You can see a big restaurant on your right. There is a bridge near the restaurant. Go across it and turn left. Then go down Bridge Street. Turn left at New Park and go down Guangming Street. Our school is across from a bank.

在25℃的实验条件下可顺利完成的是（　　）

示例：阳光：午后的阳光穿枝拂叶而来，温柔地亲吻着我的脸庞。

备选事物：月亮     枯叶     小溪

把 1，2，3，…，9填在如图的9个圆圈里，然后将任意两个相邻的数相加，得到一些和，要使这些和都不超过整数n，n至少是多少？