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NASA's Phoenix Mars Lander1 has taken its first-ever picture of a single particle of rusty Martian dust with one of its microscopes. The dust particles of dust were shown at a higher magnification than anything outside of Earth that has been imaged before. The rounded particle measured only about one micrometer,or one millionth of a meter,across.

"Taking this image required the highest resolution microscope operated off Earth2 and a specially designed device to hold the Martian dust," said Tom Pike,a Phoenix science team member from Imperial College London3. "We always knew it was going to be technically very challenging to image particles this small4."

The device that imaged the dust speck is called an atomic force microscope,which maps the shape of particles in three dimensions by scanning them with a sharp tip at the end of a spring. The atomic force microscope can detail the shapes of particles as small as about 100 nanometers. And this won't be the last dust particle that Phoenix will image5. "After this first success,we're now working on building up a portrait gallery6 of the dust on Mars," Pike said.

Dust exists everywhere on Mars,coating the surface and giving it its rusty red color. Dust particles also color the Martian sky pink and feed storms that regularly envelope the planet. The ultra-fine7 dust is the medium that actively links gases in the Martian atmosphere to processes in Martian soil,so it is critically important to understanding Mars' environment8,the researchers said.

The $420-million Phoenix mission is analyzing the dust and subsurface ice layers of Mars' arctic regions to look for signs of potential past habitability. The particle seen in the atomic force microscope image was part of a sample scooped by the robotic arm from the "Snow White" trench and delivered to Phoenix’s microscope station in early July.

练习：

1. The dust particle on Mars is the smallest particle that has been imaged outside of Earth.

A. Right B. Wrong C. Not mentioned

2. Using the same technology,we have also measured the size of particles on the moon and Jupiter.

A. Right B. Wrong C. Not mentioned

3. Scientists use the highest resolution microscope to watch and record the image of Martian particles on earth.

A. Right B. Wrong C. Not mentioned

4. Tom Pike said that they used to think it was no easy job to image such small particles.

A. Right B. Wrong C. Not mentioned

5. An electronic device has been developed to measure the weight of certain Martian rocks.

A. Right B. Wrong C. Not mentioned

6. After collecting the last Martian dust particle,the scientists have started to build up a portrait gallery of it.

A. Right B. Wrong C. Not mentioned

7. The Phoenix's robotic arm collected the Martian dust particles for analysis on Mars.

A. Right B. Wrong C. Not mentioned

答案与解析 ：

1.A第一段说,NASA的凤凰号火星登陆器用它的显微镜观测地球外长度只有百万分之一米的微粒。本题的表述与第一段的意思吻合。

2.C通篇文章都没有提到科学家用同样的技术测量月球和水星上的微粒。

3.B第一段只是说,NASA的凤凰号火星登陆器用它的显微镜观察地球外长度只有百万分之一的火星微粒,而不是地球上,所以本题的表述是错的。

4.A Tom Pike说,"We always knew it was going to be technically very challenging to image particles this small."（我们过去一直知道,观察体积如此小的微粒具有很高的挑战性。）（见第二段）这句话是选择 A的依据。

5.C通篇文章都没有提到有人发明了一种能测量火星上某些微粒的重量的电子装置。

6.B第三段中提到,"… this won't be the last dust particle that Phoenix will image"。接着又说,"After this first success,we're now working on building up a portrait gallery of the dust on Mars"。而本题却说： "After collecting the last Martian dust particle,we’re now working on building up …",这与文章所表达内容明显不同,所以本题的答案是 B.

7.A 选择 A的依据是文章最后一句： "The particle seen in the atomic force microscope image was part of sample scooped by the robotic arm …"。