题目内容
____ matter in one form is transmuted to another form , a phase change is said to have taken place .
- A.Such
- B.Then
- C.Whenever
- D.Seldom
The earth is not the only body that travels around the sun. With it are eight other planets, fellow members of the sun’s family.
Two of them, Mercury (水星) and Venus, are nearer while the other six, namely Mars, Jupiter, Saturn, Uranus, Neptune and Pluto, also in their given order from the sun, are farther from the sun than the earth is. The farther they are, the longer trips they make around the sun. People noticed long ago that these traveling bodies moved around in the sky in definite paths. It is a force called gravity that holds them in their paths.
We know that every little bit of matter in the universe pulls upon every other bit of matter. The pull between two bodies is proportional (成比例的) to the product of their masses. Because the sun is so large the pull between the sun and the planets are thus great. If it were not for this pull, the planets would fly off into space. In the same way there exists a pull between the earth and the moon, which keeps the moon traveling in its orbit around our planet, the earth. Gravity holds you to its surface, and pulls back to it the ball which you throw into the air. Of course the ball also pulls on the larger earth but the earth is so much larger that the pull is not noticed.
Now remember that large bodies exert a greater pull than smaller ones which contain less material. But each object in the universe, no matter how small, pulls on all other objects to some degree.
【小题1】There are ________ that travel around the sun in the sun’s family.
| A．nine planets | B．eight planets |
| C．one star and ten planets | D．the earth and the sun |
| A．Mercury and Venus. | B．Neptune and Pluto. |
| C．Saturn and Uranus. | D．Mars and Jupiter. |
| A．all the objects, big or small, must exert the same pull on one another |
| B．large objects exert the same pull on anybody as small objects |
| C．small objects exert the same on large ones |
| D．each object in the universe exerts a pull on all other objects |
| A．the sun and the moon is greater than between the sun and the earth |
| B．the earth and the moon is greater than that between the sun and the earth |
| C．the sun and the earth is greater than that between the earth and the moon |
| D．the sun and the earth is the same as that between the earth and the moon |
What happens inside the skull of a soccer player who repeatedly heads a soccer ball? That question motivated a challenging new study of the brains of experienced players that has caused discussion and debate among soccer players, and some anxiety among those of us with soccer-playing children.
For the study, researchers at the Albert Einstein College of Medicine in New York selected 34adults, men and women. All of the volunteers had played soccer since childhood and now competed year-round in adult soccer leagues. Each filled out a detailed questionnaire developed especially for this study to determine how many times they had headed a soccer ball in the previous year, as well as whether they had experienced any known concussions (脑震荡) in the past.
Then the players completed computerized tests of their memory and other learning skills and had their brains scanned, using a complicated new M.R.I. technique which can find structural changes in the brain that can't be seen during most scans.
According to the data they presented at a Radiological Society of North America meeting last month, the researchers found that the players who had headed the ball more than about 1,100 times in the previous 12 months showed significant loss of white matter in parts of their brains involved with memory, attention and the processing of visual information, compared with players who had headed the ball fewer times.
This pattern of white matter loss is "similar to those seen in traumatic (外伤的) brain injury", like that after a serious concussion, the researchers reported, even though only one of these players was reported to have ever experienced a concussion.
The players who had headed the ball about 1,100 times or more in the past year were also generally worse at recalling lists of words read to them, forgetting or fumbling the words far more often than players who had headed the ball less.
【小题1】The passage is most probably a______.
| A．news report | B．research report |
| C．story for soccer players | D．text for doctors |
| A．Computerized test. | B．Questionnaire.. |
| C．Scanning. | D．M.R.I. technique. |
| A．significant effect on brain | B．little effect on one's brain |
| C．nothing to do with the brain injury | D．one's memory improved |
| A．Playing soccer frequently. | B．Tests of their memory. |
| C．White matter loss. | D．Information processing. |
| A．remembering | B．misunderstanding |
| C．recalling | D．missing |