题干

孟德尔利用“假说——演绎”的方法发现了两大遗传规律.下列对其研究过程的分析中,正确的是(  )

A:在豌豆杂交、F1自交和测交的实验基础上提出问题

B:所作假说的核心内容是“性状是由位于染色体上的基因控制的”

C:为了验证所作出的假说是否正确,设计并完成了正、反交实验

D:先研究一对相对性状的遗传,再研究两对或多对相对性状的遗传

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D

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        When I was about 12, I had an enemy, a girl who liked to point out my shortcomings(缺点). Week by week her list grew: I was very thin, I wasn't a good student, I talked too much, I was too proud, and so on. I tried to hear all this as long as I could. At last, I became very angry. I ran to my father with tears in my eyes.   

    He listened to me quietly, and then he asked. “Are the things she says true or not? Janet, didn't you ever wonder what you're really like? Well, you now have that girl's opinion. Go and make a list of everything she said and mark the points that are true. Pay no attention to the other things she said.”   

    I did as he told me. To my great surprise, I discovered that about half the things were true. Some of them I couldn't change (like being very thin), but a good number I could—and suddenly I wanted to change. For the first time I go to fairly clear picture of myself.  

    I brought the list back to Daddy. He refused to take it.“That's just for you,” he said.“You know better than anyone else the truth about yourself. But you have to learn to listen, not just close your ears in anger and feeling hurt. When something said about you is true, you'll find it will be of help to you. Our world is full of people who think they know your duty. Don't shut your ears. Listen to them all, but hear the truth and do what you know is the right thing to do.”   

    Daddy's advice has returned to me at many important moments. In my life, I've never had a better piece of advice.