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问题 单项选择题

在果胶酶溶液中加入双缩尿试剂，其结果应该是（）

A.产生气泡

B.溶液呈蓝色

C.溶液呈紫色

D.产生砖红色沉淀

答案

参考答案：C

解析：果胶酶的化学本质是蛋白质，其内加入双缩脲试剂，相当于蛋白质的鉴定

阅读理解

Today almost everyone knows computers and the Internet. If I ask you “What is the most important thing in your life?” Maybe you will say “Computers and the Internet”. The first computer was made in 1946. It was big but worked slowly.    小题1:    What can computers do? A writer once said, “People can’t live without computer today.”

The Internet is about twenty-five years later than computers.   小题2:    We can use it to read books, send e-mails, do some shopping, play games and make friends.

Young men, especially the high school students like the Internet very much.    小题3:   In the Internet bars, they make friends on the Internet and maybe they have never seen these friends. They don’t know their real names, ages and even sex(性别).    小题4:    Some of them play games in the Internet bars all day and night. Many of them can’t catch up with others in many subjects because of that.

Now the government has done many things. Some gangster bars(黑网吧) have been banned(取缔).    小题5:   The teachers and parents are still worried about these children.

We can use computers and the Internet to learn more about the world. But at the same time, we should remember that computers and the Internet could not do all the things.

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选择题

月球表面富含地球上没有的能源氦-3（He-3），它是核聚变反应堆理想的燃料，可提供便宜、无毒、无放射性的能源．He-3的原子核中质子数为2、中子数为1，下列关于它的说法中不正确的是（　　）

A．核外电子数=质子数=2

B．原子结构示意图中最外层上有1个电子

C．原子序数=核电荷数=2

D．相对原子质量=质子数+中子数=3
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