阅读理解

　　Benjamin Banneker was born a few months before another great American —George Washington. Benjamin was black, but he was not a slave. He and his mother and his grandmother were free.

　　Benjamin's grandmother came from England. In America she got a job and worked for many years to pay for her boat trip across the ocean. After working many more years, she saved enough money to buy a farm. Benjamin lived with her for a while. She taught him to read and write and do arithmetic.

　　Benjamin's neighbors knew that he was clever. They were not surprised when he built a large wooden clock. He made each piece after studying a small pocket watch. The clock made him famous, for it was one of the first clocks built in America. People from other places began to send hard problems of all kinds for Benjamin to settle.

　　Thomas Jefferson learned of Benjamin Banneker's ability to settle hard problems. He asked Banneker to help build the city that was to be the capital of the United States —Washington, D.C..

　　Banneker worked hard on the plans for the city. He marked where the streets and buildings —the Capitol (国会大厦), the White House, and many others —should be built.

　　Later, L' Enfant, the Frenchman who had designed the new city, had a quarrel, and went back to France in anger. He took all of the plans with him. The workmen couldn't build without any plans to follow.

　　For a while it seemed that the plans for the capital might have to be changed. But Benjamin Banneker remembered the plans he has helped draw. He drew each again just as he once has built each piece of his clock.

　　If it weren't for Benjamin Banneker, Washington, D.C.might look very different from the way it does today.

1．Benjamin Banneker is remembered to this day mainly because ________.

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A．he made one of the first clocks in America

B．he used to be an assistant to L' Enfant, who has designed the city Washington

C．he designed the city Washington when L' Enfant left with his plans

D．he was able to build the city Washington as L' Enfant left with his plans

2．When Banneker built a large wooden clock, ________.

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A．people in America showed no surprise

B．his name spread all over America

C．he became the first man in America to build a clock

D．people came from other places to congratulate him

3．Thomas Jefferson asked Banneker to help build the city Washington because he was told that Banneker was

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4．In building the city Washington, Banneker showed ________.

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A．he has a good memory

B．he was never tired of working

C．he feared no difficulties

D．he was good at drawing

5．When L' Enfant left with his plans, Banneker was in ________ of building the Capital Washington.

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It was graduation day at the university where I work and a beautiful day quite unlike the first graduation I attended as a young professor. On that cold day years ago, as we watched the students walking into the hall, one of my colleagues（同事）turned to me and said, “Graduation will be one of the happiest and one of the saddest time of your life.” At my request, he answered, “Because the students you have got to know have to leave.”

As years went by, my previous confusion about my colleague’s words no longer existed. When I came across naughty students, I had to rethink why I chose to be a teacher. It obviously isn’t the money. Once a former computer science student of mine called me, asking me if I wanted to have a change. He was working at Nintendo Corporation. His salary was higher than my present one, though I have more education and have worked for over 10 years. With my programming skills, he said he could get me hired, I thanked him, but refused his kind offer.

A few days before this graduation, while working on final grades, I found a note a student had slipped in with her homework. She thanked me for being her teacher and said the things she had learned in my class – not about math, but about life – would be things she would remember long after the math skills had faded away. As I finished reading, I remembered why I had become a teacher.

Now, on this sunny graduation day, as I again observed the sea of blue hats and gowns, I did so with a deeper sense of satisfaction – I will always be grateful that I am a teacher.

1.Hearing his colleague’s description of graduation for the first time, the author ______.

2.The computer science student called the author because he ______.

3.The underlined phrase blue hats and gowns refers to ______.

4.We can learn from the text that the author ______.