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閱讀下面短文，從每題所給的A、B、C、D四個選項中，選出最佳選項。
Have you ever dreamed about a trip to space? Seeds(種子)of some vegetables and crops are a lot luckier than you, as they have travelled to space and back．
China is among the three countries in the world that carry out agricultural(農業的)research in space．The others are Russia and the U．S．Since 1987, China has sent about 1000 kinds of seeds into space．These include green peppers, tomatoes, cucumbers, carrots and rice．Even on China's first manned spacecraft Shenzhou V there were some seeds from Taiwan．
“Conditions(條件)in outer space such as radiation(輻射)and low gravity can cause big changes in the seeds, ” said Chinese researcher Jin Xing．
But not all seeds are better after going to space．After returning to the earth, the best seeds are chosen．These seeds produce much more and also grow faster than normal seeds．As the safety of genetically modified(轉基因)food is still being talked about, some people are not sure about the safety of these “space vegetables” because some of their genes(基因)are changed during the trip to space．
But Jin holds the more hopeful view．He said, “Unlike genetically modified crops, no new genes are introduced to the space vegetables, so they are surely safe．”
Space vegetables are better than normal vegetables．For example, space tomatoes stay fresh for twenty days, which is one week longer than normal tomatoes．Another popular space vegetable is the peppers．Space peppers have 20 per cent more vitamin C than normal peppers．
Researchers are considering holding a tomato festival．By the time people will be able to enjoy about 30 different kinds of space tomatoes on their dining tables．
So far, the Chinese Academy of Sciences has set up three space vegetable base fields, one of which is in Shenzhen while the others are in Beijing and Jiangsu Province．
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