问题 单项选择题 A1/A2型题

下列频谱多普勒超声的描述,错误的是()

A.分为连续波和脉冲波频谱多普勒

B.脉冲波多普勒具有距离选通性

C.连续波多普勒不具有距离选通性

D.脉冲多普勒的脉冲重复频率越高,测量的血流速度越高

E.显示多普勒频谱可直接测出血流量

答案

参考答案:E

解析:多普勒频谱只能了解血流性质、时相、速度、方向,不能直接测出血流量。

阅读理解

阅读理解。

    Many large cities in the United States have an area called Chinatown. Each of them was set up by people

who came from China. For example, Chinatown in San Francisco, California, began in the 1840s. The Chinese

immigrants came to America to look for gold. Then the area they lived in later became known as Chinatown.

    Chinatowns were also set up in cities in the western states of Oregon and Washington during the middle of

the 19th century. Many Chinese immigrants in these areas helped build the first railroad system across the

United States. However, after the work ended in 1869, many Chinese moved to the eastern and middle parts

of the United States.

    Chinatowns can also be found in cities outside the United States. For example, the first Chinese immigrants

in London arrived in the late 18th century. They were men who worked for the East India Company. Later,

the Chinese immigrants opened small stores and restaurants there.

    Today, many people visit Chinatown. It has special Chinese gates and walking areas for visitors. Chinatowns

around the world are not only places where Chinese people live and work. They are also places where visitors

can learn more about Chinese culture and traditions.

1. In the 1840s, a large number of Chinese people went to America to _____. [ ]

A. build the railway

B. build Chinatowns

C. work for the East India Company

D. look for gold

2. What does the underlined word "immigrants" mean? [ ]

A. 移民

B. 运动员

C. 建筑师

D. 教练

3. According to the passage, the earliest Chinatowns in Oregon were set up about _____ years ago. [ ]

A. 200

B. 160

C. 100

D. 300

4. Visitors come to Chinatowns because _____. [ ]

A. the food there is cheap

B. they can learn more about Chinese culture

C. they want to know about the earliest immigrants from China

D. they want to live there

5. What does the passage mainly tell us? [ ]

A. The history of Chinatowns in the world.

B. The visitors in Chinatowns.

C. The Chinese culture and traditions.

D. The Chinese immigrants' hard work in America.

问答题 简答题