顾炎武“天下兴亡，匹夫有责”的现实意义在于（    ）

下列叙述错误的是（）

骑兵挑错

错案：

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    Nick is my good friend from England. Now let me tell you something(一些事情)about him.   

    Nick is a student and he is thirteen years old.His family are in Beijing now.His father,Mr Brown,is a manager in a hotel. His mother,Mrs Brown, is an English teachers at his school. Nick has a sister. Her name is Kate. Now they study in the same school.Look!This is a picture of their school. It is very big. There is a tall building with 23 classrooms in the middle of the school.The library is behind the tall building. The sports hall is next to the library. A playground is in front of the sports hall. It's big too. Nick and Kate like their school in Beijing very much.

显微镜下观察小鱼尾鳍的毛细血管时，应该寻找（   ）。