题干

临床医学证明有多种病毒可经输血传播,我国科学家历经10年集智攻关,建立了“人工血液”制备工艺,并通过干细胞技术成功制备出“人工红细胞”,是干细胞、体外制备最接近临床应用的生物科技成果,为规模化生产奠定了重要基础,使我国干细胞制备“人工血液”的研发水平进入国际一流行列。这说明(    )

①实践不断提出新的需要是认识发展的动力

②人们对干细胞的探索研究决定实践的升华

③实践是检验干细胞制备技术是否正确的标准

④改造世界是人们探索干细胞制备技术的目的

A:①②

B:①④

C:②③

D:③④

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B

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    On the first day of school our teacher introduced himself and challenged us to get to know someone we didn't already know. I stood up to look around when a gentle hand touched my shoulder.

    I turned around to find a little old lady with a warm smile. She said, “Hi, handsome. My name is Rose. I'm eighty-seven years old.”

    “Why are you in university at such a YOUNG age?” I asked. She replied, “I'm here to meet a rich husband, get married, have a couple of kids, and then retire and travel.”

    I knew she was joking. I was curious what might have encouraged her to be taking on this challenge at her age.

    “I always dreamed of having a university education and now I'm getting one!” she told me. We became friends. Every day we would talk nonstop after class. I always enjoyed listening to this “time machine” as she shared her wisdom and experience with me. And Rose easily made friends wherever she went.

    At the end of the term we invited Rose to make a little speech. She cleared her throat(喉咙) and began, “We do not stop playing because we are old; we grow old because we stop playing. I've learned a few secrets to staying young, being happy, and achieving success. You have to laugh and find humor every day. You've got to have a dream. When you lose your dreams, you die.”

    “There is a huge difference between growing older and growing up. Anybody can grow older. That doesn't take any talent or ability. The idea is to grow up by always finding the opportunity(机会) in change...”