题目内容
Space travel is definitely bad for astronauts’ bones, reducing their bone density(密度) after only a month of weightlessness, according to French research published on Friday.
Laurence Vico and his fellow workers at St Etienne University called for more research into the effects of microgravity, afte
r their study of 15 astronauts from the Russian MIR station showed bone loss continued throughout space flights.
“Bone loss was especially striking in four astronauts, ”
the scientists reported in the Lancet Medical Journal.
They measured the bone mineral density (BMD) of bones in the forearm(前臂) and lower leg of the astronauts who had spent one to six months in space.
The BMD loss was significant in the tibia(胫骨) of the lower leg, a weight-bearing bone, but barely changed in the radius(桡骨) of the forearm. “Our results indicate the need to investigate not only different bones, but also different areas of the same bone since not all sites of the skeleton (骨架) are similarly affected by space conditions, ” they added.
Without gravity the body isn’t bearing any weight so there is no need for calcium (钙)
which makes bones strong, and it becomes empty into the bloodstream.
The research team suggested in future scientists should try to determine if the loss of bone density was only on weight-bearing bones on longer flights, also the possible recovery after returning to Earth.
【小题1】French scientists
did their research on Russian astronauts, because _______.
| A．they only cared for the Russian astronauts |
| B．they were not interested in their own astronauts |
| C．the Russian government invited them to do their research |
| D．the Russian astronauts worked in space for a long time |
| A．the BMD loss may cause serious illness to astronauts |
| B．the BMD loss may cause some change in astronauts’ bodies |
| C．astronauts shouldn’t care about the BMD loss |
| D．astronauts should take some calcium before space travel |
ge?| A．The food they eat in space. | B．The drinks they take in space. |
| C．The temperature in space. | D．The gravity in space. |
| A．unusual | B．simple | C．weak | D．slow |
【小题1】D
【小题1】B
【小题1】D
【小题1】A
解析
Our final man-made wonder is in the northwestern city of Seattle, Washington. The Space Needle was built as the central structure for the 1962 World's Fair. As in the field of space travel, new technologies continue to appear in undersea exploration. They share a number of similarities with each other — as well as some important differences.
Manned submersibles (潜水器), like spaceships, must maintain living conditions in an unnatural environment. While a spaceship must simply be sealed against the vacuum space, a submersible must be able to bear extreme pressure if it is not to break up in deep water.
In exploring space, unmanned vehicles were employed before astronauts. In undersea exploration, on the other hand, men paved the way, and only recently have unmanned remote-operated vehicles (ROVs) been put to use.
One reason for this is that communicating with vehicles in orbit is much easier than talking to those underwater. A vacuum is an ideal medium for radio communications, but underwater communications are limited to much slower sound waves. Thus, most undersea vehicles — particularly ROVs — operate at the end of long ropes.(电缆终端)
For a similar reason, knowing where you are undersea is much more difficult than in space. A spaceship’s position can be located by following its radio signal, or by using telescopes and radar. For an undersea vehicle, however, a special network of sonar （声纳系统）devices must be laid out in advance on the ocean floor in the area of a dive to locate the vehicle’s position.
Though undersea exploration is more challenging than outer space in a number of respects, it has a distinct advantage: going to the ocean depths doesn’t require the power necessary to escape Earth’s gravity. Thus, it remains far less expensive.
【小题1】The purpose of the passage is ______.
| A．to persuade you to explore the depths of the ocean |
| B．to stress the importance of the undersea exploration |
| C．to make you believe that the undersea exploration is better |
| D．to tell some differences between two kinds of explorations |
| A．unmanned vehicles were used in the beginning |
| B．men covered the ocean floor with stones and bricks |
| C．manned vehicles were employed before unmanned ones |
| D．men invented unmanned remote-operated vehicles in the past |
| A．from time to time |
| B．after the undersea vehicles dive |
| C．before the undersea vehicles dive |
| D．when the undersea vehicles are diving |
| A．Submersibles usually break up in deep water. |
| B．Undersea vehicles can receive signals immediately. |
| C．Going to space needs power to escape the gravity. |
| D．Radio communications are quite difficult in a vacuum. |
The space shuttle Discovery has had a long and busy career. For 27 years, it has worked for NASA, carrying astronauts to space and back on 39 missions. On March 9, 2011, after returning from its final voyage, the world’s most traveled spaceship was retired.
A crowd of shuttle workers, reporters and schoolchildren waited to greet Discovery at Kennedy Space Center in Cape Canaveral, Florida. Three minutes before noon, they watched as the shuttle appeared in the sky and made one last touchdown. “For the final time: wheels stop,” Discovery’s commander Steven Lindsey said when the shuttle rolled to a stop.
Discovery’s final trip was to the International Space Station (ISS), a giant space lab in the sky. Discovery’s crew took care of the last U.S. construction project at ISS. They delivered 10 tons of supplies for the ISS. The six-person crew also dropped off an unusual companion for ISS’s researchers: a human-like robot named Robonaut 2. Astronauts will assemble（组装）R2 at the ISS over several months.
Now, NASA is winding down its shuttle programme. NASA is to begin work on new spaceships that can travel longer distances. Discovery’s retirement is the first of three. Endeavor, another shuttle, is scheduled to make its final voyage soon. And Atlantis’s last trip is planned for the end of June.
Museums across the country have requested the retired shuttles. The Smithsonian’s Air and Space Museum, in Washington, D.C., was the lucky recipient（接收者）of Discovery. The museum’s collection contains hundreds of NASA artifacts.
Where will the other shuttles go? You’ll have to wait to find out. NASA will announce its decision on April 12, the 30th anniversary of the first space shuttle launching. Stay tuned!
【小题1】As part of the final mission, Discovery’s crew___________.
| A．carried researches to space |
| B．assembled the Robonaut 2 at the ISS |
| C．brought supplies to the ISS |
| D．went on a spacewalk |
| A．improving | B．ending | C．changing | D．testing |
| A．Discovery completed 39 missions during its two decades of space travel. |
| B．The ISS is a big project and six researchers live on the station. |
| C．American space exploration will focus on longer missions. |
| D．The shuttles Endeavor and Atlantis will make their last missions next month. |
| A．people’s opinions of Discovery’s retirement |
| B．the government’s concern about the shuttles’ future |
| C．the shuttles’ final homes after retirement |
| D．museums’ great interest in the retired shuttles |