题目内容：

An American spacecraft is moving closer to a dwarf planet(矮行星)called Ceres(谷神星). The American space agency's Dawn spacecraft is set to reach the planet-like object in March.

Space agency scientists will then place Dawn in an orbit(轨道) around the dwarf planet. Agency scientists want to know more about ice on Ceres. The spacecraft will gather clues about whether Ceres may have once had conditions to support life as we know it.

Dawn left Earth more than seven years ago on a trip to explore Ceres and another dwarf planet, called Vesta(灶神星). Both dwarf planets are in the main belt of asteroids(小行星), a group of large objects, between the planets Mars and Jupiter.

Marc Rayman is the chief engineer and director of the Dawn mission.

Scientists call Vesta and Ceres "protoplanets(行星) ". Mr. Rayman says they were in the process of becoming full-size planets when, in his words, "their growth was terminated(终止)."

Scientists believe Ceres is made of rock, and covered with ice.

The Dawn mission is based in Los Angeles, California. Scientists there send second-by-second commands to the spacecraft. They direct its every move, including telling it what pictures to take. Dawn will make a map of the dwarf planet. It will also try to discover how Ceres' surface has changed.

Carol Raymond is the deputy principal investigator(副首席研究员) of the project. He says Dawn made an unexpected discovery while orbiting Vesta.

"Instead of being bone dry, which we expected, there were patches on the surface of Vesta that showed significant amounts of water bound in the rocks and possibly even free water that could have flowed on the surface in the past."

She says that if Earth's water came from wet worlds like Vesta and Ceres, then life could have developed there, too.

If Dawn finds that the environment of Ceres could have supported life, scientists may seek to explore the dwarf planet with other scientific instruments.

Dawn will gather information about Ceres until the middle of 2016. It will then continue to orbit the small planet.

1.Which of the following about spacecraft Dawn is true?

A. It was sent into space in 2008.

B.  It is orbiting around the dwarf planet Ceres.

C.  Its destination is just the dwarf planet Ceres.

D.  It will gather information about Ceres until early 2016.

2.What’s the meaning of the underlined word “patches”?

A. spots     B. roles     C. sorts     D.  kinds

3.What do we know about Vesta?

A.  It is in the main belt of asteroids between the planets Mars and Venus.

B.  It is another dwarf planet which Dawn will explore.

C.  It is becoming a full-size planet.

D.  It is made of rock, and covered with ice.

4.The passage mainly tells us ______.

A.  Spacecraft , Dawn, is researching Ceres.

B.  What Spacecraft , Dawn,  is.

C. NASA Spacecraft, Dawn, is moving closer to a 'Dwarf Planet'.

D. How Dwarf Planet research program is carried out.