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To walk among me stars has been a dream of human kind since the beginning of time, wandering among the heavens that inspire legends and fantasies across the ages. Today, that dream has become a reality, a memory of some of the greatest human achievements in history: walking on the moon, sending probes to distant planets and discovering the secrets behind the mysteries of the cosmos. In the middle of the twentieth century, however, humans were at the halfway point between viewing space travel as a dream and as a reality. To them it was a goal rather than a memory, and the two main forces working toward that goal were the world’s two superpowers, the Soviet Union and the United States.
Both of the great nations, on the advent of incredibly efficient rocket thrusters capable of propelling manmade objects into space, strove to achieve the victory of finding a place among the stars and securing the considerable international prestige associated with
A. convince the reader that the Space Race was a positive contribution to mankind
B. educate the reader on the Space Race and its implications
C. present a hypothesis on the effects of the space program on human development
D. advocate on behalf of greater effort and investment into the space program
Why does cream go bad faster than butter Some researchers think they have the answer, and it comes down to the structure of the food, not its chemical composition — a finding that could help rid some processed foods of chemical preservatives.
Cream and butter contain pretty much the same substances, so why cream should sour much faster has been a mystery. Both are emulsions — tiny globules (小球) of one liquid evenly distributed throughout another. The difference lies in what’s in the globules and what’s in the surrounding liquid, says Brocklehurst, who led the investigation.
In cream, fatty globules drift about in a sea of water. In butter, globules of a watery solution are locked away in a sea of fat. The bacteria which make the food go bad prefer to live in the watery regions of the mixture. "This means that in cream, the bacteria are free to grow throughout the mixture," he says.
When the situation is reversed, the bact
A. are more evenly distributed in cream
B. multiply more easily in cream than in butter
C. live on less fat in cream than in butter
D. produce less waste in cream than in butter
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