题干

洋葱根尖细胞进行分裂,一个细胞分裂形成(  )

A:一个子细胞,染色体数目不变

B:两个子细胞,染色体数目不变

C:一个子细胞,染色体数目减少

D:两个子细胞,染色体数目减少

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答案(点此获取答案解析)

B

同类题2

根据短文理解,从A、B、C、D四个选项中选择最佳答案填空。

    At age 14, 15 and 16, the way we looked was the most important thing in the world to us. My friends and I wanted nothing less than perfection.

    In high school, we joined the gymnastics team, and our 1 became even more important to us. We had no fat, only muscle. On the weekends, we would go to the beach,  2 of our flat stomachs.

    One summer day, all my friends were at my house 3. At one point, I was running back to the pool. I 4 on a bee, and while it was dying under my foot, it stung (蛰) me. I instantly started to feel 5. That night, I began to run a high fever and my leg and foot were red, hot and swollen. I couldn't walk. I could barely 6.

    When my foot started to go numb, everyone became more 7. My foot was not getting enough blood. I had to go to the hospital, and my leg 8 as if it were badly broken. I couldn't move. All I could do was think about how soft my middle was becoming. That  9 me more than any concern over my leg.

    That would all 10 when I heard the doctors mention possibly cutting off my foot. It was still not getting the 11 supply it needed. The doctors would have to speed up their treatment.

    Never before did I have such great 12 for my foot. And walking seemed like a 13 from the gods. Less and less I wanted to hear my friends talk about 14 and who was wearing what. More and more I expected visits from other kids in the hospital, who were quickly becoming my friends.

    One girl came to visit me 15. Every time she came, she brought flowers. She was recovering from cancer and felt she should come back and 16 the other patients.

    She still had no hair, and she was swollen from the medications she had been taking. I would not have given this girl a second 17 before. I now loved every inch of her and looked forward to her 18.

    Finally, I was improving and soon I went home. My leg was still swollen, 19 I was walking, and I had my foot! When I would go back to the hospital, I often saw my friend. She was still visiting people and 20 good cheer. I thought if there was an angel on this earth, it had to be her.

同类题3

任务型阅读

    Last month some thieves stole a valuable teapot from a museum in Hong Kong. They took the teapot to America, but the American police found it. The museum sent Mr. Chan, a member of the museum staff, to collect the teapot. On the plane back to Hong Kong, he noticed two men. They were watching him closely. "Perhaps they're going to steal the teapot again. I must think of a plan,” he thought.

    Mr Chan's daughter, Amy, met him at Hong Kong Afimor. Mr Chan NS was carrying two boxes. He gave his daughter the pink box and said to her in a low voice, "Take this gift box home with great care." He walked away with the brown one. The two men followed him.

    Amy opened the box at home. She was expecting a pair of sports shoes, but she just found an old teapot. "This is not a very interesting gift," said Amy, a bit disappointed." That's all right. Let's make some tea in it," said her mother. Then they found a note in the teapot. It said, "Dear Amy, __ Love Dad.”

    The two men kidnapped(绑架)Mr. Chan on his way to the museum. They opened his box and found a pair of sports shoes inside."Wheres the teapot?” the two thieves shouted at the top of their voice with red faces." How dare you cheat us? We saw you give your daughter a box at the airport. Come with us! We're going to search your home, one of them said。

    When the thieves entered Mr. Chan's flat, it was dark and quiet. All of a sudden, the door closed and the lights went on. The police were waiting inside.

    Amy and her mother came out of the bedroom with the teapot. "That teapot is very valuable, said Mr. Chan. "A long time ago it belonged to an emperor. He drank tea from it."

    “We were going to drink tea from it, too, "said Amy, laughing.