题干

玉米体细胞有20条染色体,1个体细胞连续分裂2次后,形成的细胞数目和每个新细胞中的染色体数分别是( )

A:4个,5条

B:8个,10条

C:4个,20条

D:8个,20条

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C

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    I still remember an old lady, a customer on the paper route in my hometown when I was 12 years old. She taught me a lesson in1that I shall never forget.

On a(n)2afternoon, a friend and I were throwing stones onto the 3of the old lady's house. The stone that I found was too smooth,4it slipped from my hand as I let it go and5straight not for the covering on top of the house but for a small window on the house's back porch. At the sound of broken glass, we knew we were6.We turned and7.

    I was too 8 about getting caught that first night to be concerned about the old lady with the broken window in the freezing weather. However, a few days later, when I was sure that I hadn't been9, I started to feel guilty about her10.She still greeted me with a smile each day11I gave her the paper , but I was no longer able to act comfortably in her 12.

    I13my mind that I would save my paper delivering money , and in three weeks I had the seven dollars that I calculated would pay for her window . I put the money in an envelope with a note14that I was sorry for breaking her window and15that the seven dollars would cover the cost of repairing it.

    I waited until it was dark , moved16to the old lady ' s house and put the letter I didn ' t sign through the letter slot in her door . I felt 17 and could have the freedom of , once again , looking straight into the old lady's kind eyes .

    The next day, I handed the old lady her paper and was able to 18 the warm smile that I was receiving from her. She thanked me for the paper and gave me a bag of cookies she had made herself. I thanked her and proceeded(开始) to eat the cookies as I continued my19.

After several cookies . I felt an envelope and pulled it out of the bag. When I opened the envelope , I was 20. Inside were the seven dollars and a short note that said , " I'm proud of you.”