Part B
Directions: You will hear four dialogues or monologues. Before listening to each one, you will have 5 seconds to read each of the questions which accompany it. While listening, answer each question by choosing A, B, C or D. After listening, you will have 10 seconds to check your answer to each question. You will hear each piece ONLY ONCE.
听力原文: We use all sorts of services without thinking how we get them. But such services cost money. We pay for them through taxes. What would happen if everyone in a city stop? The street might not be cleaned. There would be no police force to protect people and property.
The chief duty of every government is to protect persons and property. More than three-fourths of the money spent by our government is used for this purpose. The next largest amount of public money goes to teach and train our citizens. Billions of dollars each year are spent on schools and libraries. Public money is used to pay the teachers and other public officials.
Years ago the government made money from the sale of public lands. But most of the best public lands has now been sold. The money raised was used up to help pay the cost of government. There are still some public lands that contain oil, coal, gas, and other natural products. They could be sold, but we want to save them for future years. So we all must pay our share for the services that make our lives comfortable.
What's the chief duty of every government?
A.To protect persons and property.
B.To collect taxes.
C.To teach and train citizens.
D.To save natural resources for future use.
第1题
有三个关系R、s和T如下:由关系R和S通过运算得到关系T,则所使用的运算为()。
A. 合并
B. 交
C. 广义笛卡尔积
D. 连接
第4题
有如下三个关系R、S和T:由关系R和S通过运算得到关系T,则所使用的运算为()。
A.笛卡儿积
B.交
C.并
D.自然连接
第5题
有如下三个关系R、S和T:由关系R和S通过运算得到关系T,则所使用的运算为()。
A.笛卡儿积
B.交
C.并
D.自然连接
第6题
有三个关系R、S和T如下:由关系R和S通过运算得到关系T,则所使用的运算为()。
A.笛卡尔积
B.交
C.并
D.自然连接
第7题
有三个关系 R , S 和 T 如下:
由关系 R 和 S 通过运算得到关系 T, 则所使用的运算为
A) 并
B) 自然连接
C) 笛卡尔积
D) 交
第8题
有三个关系R、S和T如下:
由关系R和s通过运算得到关系T,则所使用的运算为()。
A.并
B.自然连接
C.笛卡儿积
D.交
第9题
有三个关系R、S和t如下:
由关系R和s通过运算得到关系T,则所使用的运算为()。
A.笛卡儿积
B.交
C.并
D.自然连接
第10题
有三个关系R、S和T如下:
由关系R和S通过运算得到关系T,则所使用的运算为()。
A.笛卡尔积
B.交
C.并
D.自然连接
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