《白雪歌送武判官归京》中将诗人因朋友离去而产生的无限惆怅之情抒写到了极致，这两句诗是：____，____。

    Hi, everyone. I'm glad to show you around our city.

Now we are standing at Qingnian Square. ____ It is the white building over there. And it's on Changqing Street. Next to the bank is a bookstore. Many people go there to buy books. Go along Changqing Street.____. It is at the end of the street. Then turn left into Hengshan Road, and our school is on the right____. We sometimes walk along Hengshan Road to go to the swimming pool after class.____ Oh, there is a small river outside the city. ____ It is great fun.

从A, B, C, D四个选项中选择恰当的句子填入文中空缺处，使内容完整，正确。

神经系统活动的基本方式是 ____ ；神经系统的最高级中枢是____ ．