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56. The sentence "Saying ’yes’ to yourself" means ________.
A. you can have more time to play with others
B. you needn’t care about other’s feeling if you are happy
C. you are selfish and treat others rudely
D. you can deal with your business as you have planned
57. When you say "no" to others you should say it in a ________.
A. secret way B. polite way C. proud way D. guilty way
58. In Watson’s opinion, people can save much time on condition that ________.
A. they say "no" at a suitable time B. they say "no" as much as possible
C. they are afraid of saying "no" D. they make others angry at them
59. If a person says "no" to everything, the result he or she receive may be that he or she _______.
A. enjoys a wonderful life B. makes a lot of money
C. faces difficulty in life D. forgets to say "yes" in the end
B
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.
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.
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