某学生进行蔗糖的水解实验，并检验水解产物中是否含有葡萄糖。他_爱下问搜题

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问题选择题

某学生进行蔗糖的水解实验，并检验水解产物中是否含有葡萄糖。他的操作如下：取少量纯蔗糖加水配成溶液；在蔗糖溶液中加入3-5滴稀硫酸；将混合液煮沸几分钟、冷却；在冷却后的溶液中加入新制Cu(OH)₂浊液，加热。实验结果没有砖红色沉淀产生。其原因是[ ]

A．蔗糖尚未水解

B．蔗糖水解的产物中没有葡萄糖

C．加热时间不够

D．煮沸后的溶液中没有加入适量碱来中和作催化剂的酸

答案

答案：D

完形填空

It was the middle of my third grade, and I always lied for no reason about many things. Later, I realized that I was labeled(标签为) a liar, and my parents did not_____ me. Therefore, I promised to_____telling lies.
A few days later, my sister and I were invited to spend the weekend with my aunt. On that day, someone took one of Aunt Kim’s erasers and_____it across the top of the TV. The eraser ruined the shiny_____of the TV. When Aunt Kim discovered the destrction, all three of us were called into the TV room and asked to tell the____. Nobody did! The next thing I knew was that she was on the phone with my parents and they were on their way to____ me up.
It must be me! I was the_____. I was taken home and sent to my room. I begged them to believe that I was innocent, but no one______.
I stayed in my room the rest of that day. My parents_____let me out for dinner. And then there was a knock at the front door. Aunt Kim was standing there. It turned out that my younger sister finally felt_____! She_____that she was the one who rubbed the eraser on the TV. Aunt Kim had come to get me. I was invited back!
I don’t even remember being_____at my sister. I learned a valuable lesson about lying. A liar is not believed when he tells the truth.No matter how big or_____your lie is, once you are labeled a liar, _____trust takes a lot of work and time. I promised myself right then_____to lie again.

D．immediately

单项选择题

在胰腺炎的发病过程中起主要作用的酶是

A．糜蛋白酶

B．胰蛋白酶

C．胰血管舒缓素酶

D．磷脂酶A

E．弹力纤维酶