小强乘坐从成都开往峨眉的动车，当动车进入峨眉境内时他感慨地说：“我终于来到峨眉了！”，他说出这句话时所选择的参照物是（　　）

蛇、蜥蜴的皮肤表面覆盖着无数角质细鳞，其主要作用是(    )

某居民大院统计本月份每户用电情况，其中用电40度的有3户，用电50度的有4户，用电32度的有5户，则平均每户用电（   )

如下图是智能扶手电梯工作原理图，其中R是压敏电阻，电磁铁上端是____极。电梯无乘客时，电磁铁磁性极弱，衔铁与触点1接触；当有乘客时，R的阻值减小，磁性变____ ( 选填“强”或“弱”)，使衔铁与接触点2接触，通过电动机的电流变____ (选填 “大”或“小”)，电动机转动变快，使电梯运动变快。

根据短文内容，选择正确答案。
B
    Nick is my pen pal. He is 12 years old. He is from Canada. He lives in Ottawa. He speaks English and French. His favorite subject is science. He likes Chinese, too. And he says he can speak a little Chinese, but he can't write in Chinese.
    Nick likes sports, too. He likes swimming best. He goes swimming on weekends with his father. He says he can swim very well. He doesn't like physics. He thinks it's too difficult.
    Nick has a big family. There are nine people in his family, his grandpa, grandma, father, mother and his brothers and sisters. He has two brothers and two sisters. They are Bob, Tim, Jane and Susan. They are happy!