阅读下列内容, 从每小题所给的 A、B、C、D 四个选项中选择一个最佳答案。
Who is the greatest teacher in Chinese history? Many people would think of Confucius(孔子), whose birthday was September 28. Although he lived over 2, 000 years ago, people still remember and respect him for his contribution(贡献) to the education today.
Confucius lived in the Kingdom of Lu, which lies in Shandong Province. He lived during the Spring and Autumn Period. He had a hard childhood. His father died when he was only 3. His mother brought him up. As a child, he had to work to help his mother, but young Confucius didn't give up studying. He visited many famous teachers and learned music, history, poetry and sports.
Later, he became a teacher and started the first public school in Chinese history. At that time only children from noble families could go to school, but Confucius believed everyone should go to school if they wanted to learn. He had about 3, 000 students in his lifetime.
Today, people still follow Confucius' lessons. He told us that we all have something worthy to be learned. “When I am with three people, one of them must be better than me in some areas. I choose their good qualities and follow them.”
He also taught us that thinking is very important in study. “All study but no thinking makes people puzzled (困惑的). All thinking but no study makes people lazy.” Confucius is not only a great teacher, but also a famous thinker with wise thoughts about the world and society. His most important teachings are about kindness and good manners. “A person should be strict with himself, but be kind to others.” he said.
、重为12N的物块放入水中，当它静止时所处的状态及受到的浮力大小分别为（g取10N/kg）（ ）