问题 单项选择题

对下列二叉树进行中序遍历的结果是( )。

答案

参考答案:C

解析: 遍历就是不重复地访问二叉树的所有结点。二叉树遍历的方法有3种:前序遍历、中序遍历和后序遍历。记住3种遍历的顺序:
①前序,访问根→按前序遍历左子树→按前序遍历右子树。
②中序,按中序遍历左子树→访问根→按中序遍历右子树。
③后序,按后序遍历左子树→按后序遍历右子树→访问根。
所以对该二叉树的中序遍历结果为GDBEHACF。

单项选择题
阅读理解

阅读理解。

     In 1977, Jack, an Italian-American who lived in San Francisco, flew from America to Italy to visit his

relatives. On the way, the plane made a one-hour stop to refuel (加油) at the New York Airport.

     Thinking that he had arrived, Jack got out and spent three days in New York, believing he was in

Rome.

     When his relatives were not there to meet him, Jack thought they had been caught in the heavy Roman

traffic mentioned in their letters. While looking for their address, Jack could not help noticing that

modernization had changed most, if not all, of the ancient city's landmarks. He also noticed that many

people spoke English with strong American accent. However, he just thought that Americans got

everywhere. He also believed that so many street signs were written in English especially for the

Americans. Jack spoke very little English himself so he asked a policeman in Italian the way to the bus

station. As chance would have it, the policeman came from Italy and replied in the same language. After

twelve hours traveling round on a bus, the driver handed him over to a second policeman. After brief

argument with the policeman, Jack was very surprised to find that the Rome police had employed someone who did not speak his mother tongue.

     Jack did not believe he was told that he was in New York. In order to get on a plane to San Francisco, the policeman raced him to the airport in a police car with sirens (报警器) screaming. "See," he said to his interpreter. "I know I'm in Italy. That's how they drive."

1. Where did Jack live?

A. In Italy              

B. In San Francisco    

C. In New York        

D. The story doesn't mention

2. Why did Jack spend three days in New York?

A. He thought he had arrived in Italy

B. He did not want to go to Italy

C. He wanted to see some relatives first in New York

D. He wanted to have short rest in New York

3. Which of the following is Not true?

A. The first policeman could speak Italian fluently

B. The second policeman could not speak Italian at all

C. Jack had a brief argument with the second policeman

D. Jack could speak much English