Hi! I'm Tony. I love 1! I always get up late on weekends. For breakfast, I only have 2. It's usually an apple. I have a big lunch. After lunch, I like to eat ice-cream. It 3 good. In the afternoon，I like to 4. I usually play basketball. Sometimes I swim. In the evening, I clean the house—I like 5rooms. I always go to bed late，at about 23: 00.

    But my sister doesn't like weekends. She has a job in a big store and she always works on weekends. She never goes out 6 her friends. She usually 7 home from work at 22:00. she 8 in bed after she takes a shower. But don't ask her 9 she reads. She always falls asleep (睡着) after 10 one or two pages (页).

恩格斯说：“假如不曾有拿破仑这个人，那么他的角色会由另外一个人扮演的，这点由下面的事实可以证明，即每当需要这样一个人的时候，他就会出现，如凯撒、克伦威尔等。”这段话的含义是

等差数列$\left\{a_n\right\}$的前n项和为$S_n$，若$a_3+a_7+a_{11}=12$，则$S_{13}$等于（   ）