问题 问答题 简答题

离心泵和轴流泵的优点?

答案

参考答案:

1、效率高;

2、能直接由电动机驱动;

3、启动迅速;

4、出水量均匀;

5、容易调节;

6、工作性能比较可靠;

7、可制造各种压力和流量的水泵。

问答题 简答题
阅读理解

It's not the flashiest car in the world. Not even close. But the 1971 Volkswagen named Helioscan do something most cars can't: nm on solar energy – energy from the sun's light and heat!

Joshua Bechtold, 14, and the other students at the Riverside School in Lyndonville, Vermont, worked many months to get Helios ready for the 1999  American Tour de Sol ("Sol" is the Latin word for "sun"). They named their car after Helios, the sun god in Greek mythology(神话).

The 4-year-old Tour de Sol encourages the use of "green", or environmentally friendly, cars to help reduce pollution and save energy. It’s not a race. Cars are  judged on fuel efficiency(耗油量) rather than speed. In the week-long event, 44 cars took the 350-mile tour from Waterbury, Connecticut, to Lake George, New York. Of the 23 student cars, Helios was the only one built by middle school students.

A teacher drove Helios, but the children talked with people wherever they stopped along the mad. "That was my favorite part," says Anna Browne, 15. "We explained how the car runs.”

Due in part to old, inefficient batteries(电池), Helios finished fourth - out of four - in its kind, the sun-powered class. "We were there for the fun of it," Anna says. "We're proud of Helios," says Ariel Gleicher, 14. "It's a car that's good for the environment."

64. What is special about the car Helios in the text?       

A. It was built by middle school students.

B. It has an attractive design.

C. It was made in 1971.

D. It won the fourth prize.

65. How many sun-powered cars took part in the race?      

A. 1.       B. 4.     C. 23.    D. 44.

66. What would be the best title for the text.'?       

A. The Making of Helios

B. 1999 American Tour de Sol

C. Sun-powered Cars on the Road

D. Use of Green Cars in Connecticut

67. The students felt proud of Helios because______.

A. it could run as far as 350 miles     B. it was favored by many children

C. it had high-quality batteries         D. it was driven by clean energy