题干

科学家把从小鼠胚胎干细胞中分离获得的4个基因通过病毒导入已分化的小鼠成熟细胞,发现成熟细胞返回到了未成熟的干细胞状态。这种干细胞(iPS细胞)又能在不同条件下分化形成神经细胞等多种细胞。下列叙述不正确的是( )

A:此实验过程中病毒发挥了载体的功能

B:此实验过程中运用了动物细胞培养技术

C:分化形成的神经细胞能进行遗传信息的表达

D:iPS细胞分化形成的多种细胞所含核基因不同

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答案(点此获取答案解析)

D

同类题2

根据短文内容,选择最佳答案。

    In the United States, when one becomes rich, he wants people to know it. And even if he does not become very rich, he wants people to think that he is. That is what “keeping up with the Joneses” is about. It is the story of someone who tried to look as rich as his neighbors.

    The expression was first used in 1913 by a young American called Arthur Momand. He told this story about himself. He began earning $ 125 a week at the age of 23. That was a lot of money in those days. He got married and moved with his wife to a very wealthy neighborhood outside New York City. When he saw that rich people rode horses, Momand went horseback riding every day. When he saw that rich people had servants, Momand and his wife also hired a servant and gave big parties for their new neighbors.

    It was like a race, but one could never finish his race because one was always trying to keep up. The race ended for Momand and his wife when they could no longer pay for their new way of life. They moved back to an apartment in New York City.

    Momand looked around him and noticed that many people do things just to keep up with rich lifestyle of their neighbors. He saw the funny side of it and started to write a series of short stories. He called it “Keeping up with the Joneses” because “Jones” is a very common name in the United States. “Keeping up with the Joneses” came to mean keeping up with rich lifestyle of the people around you. Momand's series appeared in different newspapers across the country for over 28 years.

    People never seem to get tired of keeping up with the Joneses. And there are “Joneses” in every city of the world. But one must get tired of trying to keep up with the Joneses because no matter what one does, Mr. Jones always seems to be ahead.

同类题4

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

    When I was 12, all I wanted was a signet (图章) ring. They were the "in" thing and it seemed every girl except me had one. On my 13th birthday, my Mum gave me a signet ring with my initials(姓名首字母) carved into it. I was in heaven.

What made it even more special was that it was about the only thing that wasn't being "re placed". We'd been burnt out in fires that swept through our area earlier that year and had lost everything—so most of the " new" stuff (东西) we got was really just to replace what we'd lost. But not my ring. My ring was new.

    Then, only one month later, I lost it. I took it off before bed and it was missing in the morning. I was sad and searched everywhere for it. But it seemed to have disappeared. Eventually, I gave up and stopped looking for it. And two years later, we sold the house and moved away.

    Years passed, and a couple of moves later, I was visiting my parents' when Mum told me that she had something for me. It wasn't my birthday, nor was it Easter or Christmas or any other gift-giving occasion. Mum noticed my questioning look. "You'll recognize this one," she said, smiling.

Then she handed me a small ring box. I took it from her and opened it to find my beautiful signet ring inside. The family who had bought our house 13 years earlier had recently decided to do some redecorations, which included replacing the carpets. When they pulled the carpet up in my old bedroom, they found the ring. As it had my initials carved into it, they realized who owned the ring. They'd had it professionally cleaned up by a jeweler before sending it to my mother. And it still fits me.