题干

下列说法正确的是(  )

①吡罗红使DNA呈现红色,甲基绿使RNA呈现绿色  

②健那绿能使活细胞中的线粒体呈现蓝绿色  

③果糖能与斐林试剂发生作用生成砖红色沉淀 

④脂肪可以被苏丹Ⅲ染成红色 

⑤蛋白质与双缩脲试剂发生作用产生紫色反应.

A:①②③

B:③④⑤

C:①③⑤

D:②③⑤

上一题 下一题 0.0难度 选择题 更新时间:2019-05-26 07:39:57

答案(点此获取答案解析)

D

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    It was dangerously cold. A few drivers slipping and sliding off the road and back on again had cut deep ruts(车辙)in the mud. And the ruts became frozen solid. The drum of our truck's aging engine worried us.

    Trees and bushes heavy with snow bent to form an icy tunnel. We inched along the scary route as Howard grasped the steering wheel(方向盘)tightly, trying to keep the truck in the ruts. We were now riding through a nightmare with no going back. I kept praying the truck would not quit.

    However, the engine's coughing grew worse. We came to a bumping stop. Hot tears ran down my face. We noticed a small house off in the distance. “I will go for help.” Howard's words ruined my common sense and panic took over. We would take the children — we would walk to that house together!

    But the snow was deep, and our two children, asleep in the cab, were too heavy to carry. My husband convinced me to let him go alone. If no one was home or they didn't answer the door, he would come back and we'd try to hike out to a main road. For now, it was safer in the truck. I wish I could say I have faith, but when he walked away, I was mad at the world.

    It seemed as if hours had passed before I heard a familiar voice and a kind laugh of another man as they approached in the snow. The older fellow invited us to go up to the house where his wife was waiting. Two wide-awake kids moved across the seat, ready for adventure. Their voices and laughter carried in the cold night air. When we finally got close, a cheerful woman opened the door. Warm air and the smell of hot buttered popcorn and chocolate drew us in.

     Relieved, my prayers were heard!