Atoms (原子) are all around us. They are the bricks of which everything is made. Millions of atoms are held in just one grain of s

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问题    Atoms (原子) are all around us. They are the bricks of which everything is made. Millions of atoms are held in just one grain of salt, but in spite of their small size they are very important. The way an everyday object acts depends on what kind of atoms are in it and how they act.
   For example, you know that most solid objects melt (熔化) if they get hot enough. How does it happen? It is the effect of the heat on the object’s atoms. All atoms move constantly. When they are hot, they move faster.
   Usually the atoms in an object hold together and give the object its shape. But if the object grows hot, its atoms move so fast that they break the force that usually holds them together. They move out of their usual places so that the object loses its shape. Then we say that the object is melting.

选项 A、atoms are made up of bricks
B、atoms are made of everything
C、they are the same in size
D、everything is made of atoms

答案D

解析 本题题干问“为什么原子像砖一样”。原文第1段第2句话指出原子是组成的所有事物的基本元素。因此选项D. everything is made of atoms是正确答案。
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