题目

据英国《自然》杂志报道，科学家最近研制成了以锶原子做钟摆的“光晶格钟”，成了世界上最精确的钟。已知一种锶原子的相对原子质量为88，其质子数是38，则这种锶原子的中子数为A.38 B.50 C.88 D.126 答案：【答案】B【解析】质子数+中子数=质量数，一种锶原子的相对原子质量为88，其质子数是38，则这种锶原子的中子数为88-38=50，故选B。阅读下面材料，从每题所给的三个选项（A、B和C）中，选出最佳选项。 Martin Luther King was born in Georgia, U.S.A. When he was a boy, he sang with other children in the church. Little Martin knew that it was very important to love and be kind to others. Although the church was very important to Martin, he was interested in other things, too. He liked sports very much. He was not tall, but he was very strong. The boys in his town often met at Martin’s house for a game of football or basketball. Martin liked school and was a very good student. He went to college at fifteen. At first, he didn’t know what he wanted to study. He knew the black people didn’t have the same rights as the white people, and he also knew that the black people were not as happy as the white people. He wanted to work for the black people. He wanted to help the poor black people. Later he really became a famous man. He was fighting for the men’s rights all his life. At the age of thirty-five, Martin Luther King was the youngest man to have received the Nobel Peace Prize. He became not only the symbolic leader of American blacks but also a world figure. He was murdered(谋杀) on the evening of April 4, 1968. 1.Martin was from_______. A. America                                           B. England                                            C. Japan 2.When Martin was a boy, _______. A. he didn’t like singing B. he was not strong C. he enjoyed playing football and basketball 3.When Martin was a little boy, he knew that it was very important_______. A. to like sports        B. to go to the church C. to love and be kind to others 4.Marin knew that_______.    A. he would not study again    B. he would work for the black people    C. the black people had the same rights as the white people 5.Martin was famous all over the world because _______.    A. he was a kind man B. he fought for the men’s rights    C. he was murdered