3. B。判断题。从文章第2段第2句话…the
answer depends on technology and our ability to use it widely 可以肯定答案选B。
(8)
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, after 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.