题干

下列有关实验的叙述中正确的是(   )

A:若以矮茎豌豆为母本,高茎豌豆为父本进行杂交实验,则在母本和父本植株上均可收获高茎豌豆

B:探究温度对淀粉酶活性的影响实验中,可以通过本尼迪特试剂检验是否有麦芽糖的生成来反映结果

C:叶绿体色素提取实验中加入二氧化硅可以对色素进行保护

D:将人的红细胞置于蒸馏水中一段时间,若加入双缩脲试剂振荡可以看到紫色反应

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A

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    If you want to become a better reader, what should you know about speed of reading?

    Some people read very rapidly(快速地),while others read very slowly. But which one is better?

    The rapid reader may be a good reader when he reads a storybook for fun. But he may not be able to slow down enough to read directions carefully. He may read so rapidly that he does not take time to understand fully the ideas and information which are important to remember.

    The slow reader may be a good reader when he reads directions for making something. But he may spend too much time in reading a simple story which is meant to be enjoyed but is not important enough to be remembered.

    So, you see, either a rapid reader or a slow reader is not really a good one. If you wish to become a better reader, here are four important things to remember about speed of reading.

    1  Knowing why you are reading will often help you to know whether to read rapidly or slowly.

    2  Some things should be read slowly throughout. Examples are directions for making or doing something, science and history books, and Maths problems. You must read such things slowly or remember each important step and understand each important idea.

    3  Some things should be read rapidly throughout. Examples are simple stories for enjoyment, letters from friends and bits of news from hometown papers.

    4  In some of your reading, you must change your speed from fast to slow and slow to fast, as you go along. You will need to read certain pages rapidly and then slow down and do more careful reading when you come to important ideas.