试题与答案

设关系R和关系S的元素分别是4和5,关系T是R与S的笛卡尔积,即:T= R×S,则关

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题目:

设关系R和关系S的元素分别是4和5,关系T是R与S的笛卡尔积,即:T= R×S,则关系T的元数是( )。

A.9

B.16

C.20

D.25

答案:

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                                                 The History of the English Dictionary

     In 1746, Samuel Johnson began to work on his most famous book, the Dictionary of the English Language. It took him nine years to complete and in that time, he wrote meanings for more than 40,000 words.

 It was the first English dictionary to include so many words.

     Johnson was born in Staffordshire, Britain in 1709. His father was a bookseller and the family was not

 very rich. Johnson was a very clever student and he went to Oxford University in 1728. After Oxford,

 he became a school teacher but he was not happy about his job. In 1735, he married a woman named

 Elizabeth Porter. He was twenty-five years old and she was forty-six.

     A few years after that, Johnson got a job to write the English dictionary. He worked in a house in 

 London and he had six men to help him. To write the dictionary, Johnson looked for words used by the

 important English writers in those days. He underlined the sentences where the words were used and

 wrote them in his notebooks. Then he gave his notebooks to his workers and they wrote the words and

 the sentences out neatly. After that, they put the words in order according to the English alphabet. Once

 that was done, Johnson would write the meanings for the words.

     When it was completed, the Dictionary of the English Language became famous and it was used by

 many people in that time. Johnson was a happy man because of that, but his wife died before the

 dictionary was completed and she never got to share her husband's happiness.

     Johnson died in London in 1784. In his lifetime, he not only wrote the Dictionary of the English

 Language but he also wrote many poems and famous articles.

1. When Johnson started to work on the Dictionary of the English Language he was ____

    A. poor

    B. thirty-seven years old

    C. a school teacher

    D. a clever student

2. Elizabeth Porter ______.

    A. was older than Johnson by twenty-one years

    B. helped Johnson to get the dictionary writing job

    C. was a sick woman

    D. died before the dictionary was completed because she was too old

3. The Dictionary of the English Language was the first ______.

    A. dictionary to include so many words

    B. dictionary in the world

    C. dictionary that was written in England

    D. English dictionary to have 40,000 words

4. It took ______ people ______ years to complete the Dictionary of the English Language.

    A. eight; nine

    B. six; nine

    C. six; seven

    D. seven; nine

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