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!

“苟利国家生死以，岂因祸福避趋之”民族英雄林则徐的这一诗句，这句诗体现的人生价值观是：（    ）
①人生的价值在于对社会的贡献  ②有价值的人生不应考虑个人利益  ③对社会的贡献大小决定了人生价值的高低  ④个人对社会的贡献以社会对个人的尊重为基础

小明要制作一个铝合金框架式书架，他最好采用那种连接方式：（   ）  

下列各组词语中，有错别字的一组是(　　)

有X、Y两种元素，原子序数≤20，X的原子半径小于Y，且X、Y原子的最外层电子数相同(选项中m、n均为正整数)。下列说法正确的是