题干

以下生物实验中描述正确的是(  )

A:探索淀粉酶对淀粉和蔗糖的专一性作用时,可用碘液替代斐林试剂进行鉴定

B:对酵母菌计数时,用吸管吸取培养液滴满血球计数板的计数室及其四周边缘,轻轻盖上盖玻片后即可镜检

C:噬菌体侵染细菌的实验与细菌转化实验相同,都是根据遗传物质在亲子间具有连续性而设计的

D:用两种不同浓度2,4﹣D溶液分别处理月季插条形态学下端,观察并比较扦插后的生根条数会发现低浓度2,4﹣D处理的插条生根数多

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C

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    I do not know why I came to the decision to become a loser, but I know I made the choice at a young age. Sometime in the middle of fourth grade, I stopped 1. By the time I was in seventh grade, I was your2degenerate (颓废): lazy, rebellious, and disrespectful. I had lost all social 3 I terminally (不可救药的) followed, what was fashionable.

    Not long after that, I dropped out of school and 4 my downward spiral. Hard physical labor was the5for the choices I made as an adolescent. At the age of twenty-one, I was6 lost and using drugs as a way to deal with the fact that I was uneducated and7 in a dead-end job carrying roof materials up a ladder all day.

    But now I believe in do-overs, in the8 to do it all again. And I believe that do-overs can be made at any point in your life, if you have the right 9 Mine came from a10source.

    It was September 21, 2002, when my son Blake was born. It's funny that after a life of 11responsibility, now I was in charge of something so 12Over the years, as I grew into the title of Dad, I began to learn something about myself13 Blake and I were both learning to walk, talk, work, and play for the first time. I began my do-over.

    It took me almost three years to learn 14to read. I started with my son's books. Over and over, I practiced reading books to him15 I remembered all the words in every one of them. I began to wonder if it was possible for me to go back to school. I knew I wanted to be a good role model,16 after a year-and-a-half and a lot of hard work, I passed my GED test on my son's fourth birthday. This may not sound like 17and I am not trying to get praise for doing something that should have been done in the first place, but all things considered it was one of the18days in my life. Today, I am a full-time college student, studying to become a sociologist.

    Growing up, I19 heard these great turn-around stories of triumph over shortcomings. But I never thought they applied to me. Now I believe it is a (an)20anyone can make: To do it all over again.