问题 填空题

我们规定:将一个平面图形分成面积相等的两部分的直线叫做该平面图形的“面线”,“面线”被这个平面图形截得的线段叫做该图形的“面径”(例如圆的直径就是它的“面径”).已知等边三角形的边长为2,则它的“面径”长可以是     (写出1个即可).

答案

(答案不唯一)。

如图,根据“面径”有定义,

(1)等边三角形的高AD是三角形的最大面径,

(2)当EF∥BC时,若EF为面径,则EF是三角形的最小面径:

∴它的面径长可以是(或介于之间的任意一个实数)。

阅读理解

Two Chinese spacecrafts successfully completed China’s first space docking early November 3, 2011, which has taken the country a step closer to building its own space station.

Nearly two days after its launch, the unmanned spacecraft Shenzhou VIII docked with the space lab module Tiangong I more than 343 km above the earth surface. Shenzhou VIII and Tiangong I took apart after flying together for 12 days. On the 14th of November, the two spacecrafts finished the second docking. Then Shenzhou VIII parted from Tiangong I again and returned to the earth safely on the 17th. Tiangong I is still traveling around the earth in the space, waiting for the arrival of Shenzhou IX and X and so on in the near future.

That marked another great leap for China’s space program and made China the third country in the world, after the United States and Russia, to master the space docking technique (空间对接技术).

The world’s first space docking was achieved in 1966, when the manned U.S, spacecraft Gemini 8 (双子星8号) docked with an unmanned Agena Target Vehicle (阿金纳目标飞行器). Space docking is necessary to explore space beyond Earth’s orbit. “The capability increases China’s ability to act independently in space, as well as its ability to work together with others,” said Gregory Kulacki, a U.S. space scientist and senior analyst.

“With the success of its first space docking, China is now equipped with the basic technology and ability required for the construction of a space station,” said Zhou Jianping, chief designer of China’s manned space program.” The country is on its way to building a permanent manned space station around 2020.”

小题1:What did the success of the first space docking mean to China?

A.China has caught up with the United States in the space exploration field.

B.China took a step closer to building its own space station.

C.China became the first country to master the space docking technique.

D.China has the ability to build a permanent manned space station right now.小题2:What does the underlined word “That” in the third paragraph refer to?

A.Shenzhou VIII.

B.Tiangong I

C.The Space Station

D.The success of China’s first space docking小题3:What can we learn from the passage? 

A.Tiangong I will fly in the space for 12 days.

B.The first space docking of the world was achieved in 1966, by Russians.

C.Without space docking technique people can’t explore space beyond Earth’s orbit.

D.The U.S.A helped China achieve the first space docking.小题4:What’s the best title of this passage?

A.The first space docking of China.

B.The history of space docking.

C.The first space docking of the world.

D.The space docking technique

单项选择题