题干

关于生物组织中还原糖的鉴定,下列叙述正确的是(    )

A:量取2mL斐林试剂时应优先选用10mL量筒而不用5mL量筒

B:隔水加热时,试管中液体的液面应低于烧杯中水的液面

C:在组织样液中加入斐林试剂后试管内液体呈现无色,加热后变成砖红色

D:实验结束时将剩余的斐林试剂装入棕色瓶,以便长期保存备用

上一题 下一题 0.0难度 选择题 更新时间:2020-03-21 06:41:16

答案(点此获取答案解析)

B

同类题3

阅读理解

    I was sure that I was to be killed. I became terribly nervous. I searched in my pockets to see if there were any cigarettes, which had escaped their search. I found one and because of my shaking hands, I could barely get it to my lips. But I had no matches, they had taken those. I looked through the bars at my jailer. He did not make eye contact with me. I called out to him “Have you got a light?” He looked at me, shrugged and came over to light my cigarette. As he came close and lit the match, his eyes inadvertently(不经意地)locked with mine. At that moment, I smiled. I don't know why I did that. Perhaps it was nervousness, perhaps it was because, when you get very close, one to another, it is very hard not to smile. In any case, I smiled. In that instant, it was as though a spark jumped across the gap between our two hearts, our two human souls. I know he didn't want to, but my smile leaped through the bars and generated a smile on his lips, too. He lit my cigarette but stayed near, looking at me directly in the eyes and continuing to smile.

    "I kept smiling at him, now aware of him as a person and not just a jailer. And his looking at me seemed to have a new dimension too. “Do you have kids?” he asked. “Yes, here, here.” I took out my wallet and nervously fumbled for the pictures of my family. He, too, took out the pictures of his family and began to talk about his plans and hopes for them. My eyes filled with tears. I said that I feared that I'd never see my family again, never have the chance to see them grow up. Tears came to his eyes, too. "Suddenly, without another word, he unlocked my cell and silently led me out. Out of the jail, quietly and by back routes, out of the town. There, at the edge of town, he released me. And without another word, he turned back toward the town.

    “My life was saved by a smile.” Yes, the smile― the unaffected, unplanned, natural connection between people. I really believe that if that part of you and that part of me could recognize each other, we wouldn't be enemies. We couldn't have hate or envy or fear!