新章节

Some materials allow light to pass through them, others allow only some light through and others block all the light and create a dark shadow on any surface beyond them, where the light cannot reach. Mirrors can be used to redirect a light beam.

::有些材料允许光线通过，有些材料只允许一些光线通过，而另一些材料则阻挡所有光线，并在光线无法到达的任何表面上形成阴影。镜子可以用来改变光束的方向。

I am almost always with you.

I go where you go.

If you walk to school, I walk to school.

At times, I am in front of you.

Other times, I am behind you.

::我几乎总是和你在一起。你去哪儿我就去哪儿。如果你步行去学校，我步行去学校。有时候，我在你面前。其他时候，我支持你。

Am I ever not there?

If it is cloudy, I am not there.

If you are in a dark room, I am not there.

Do you know what I am?

::我曾经不在那里吗？如果是阴天，我不在那里。如果你在黑暗的房间里，我不在那里。你知道我是什么吗？

At times, I am really tall.

Other times, I am very short.

It really just depends.

If you are outside in the morning, I am tall.

In the late afternoon, I am also very tall.

Around noon, I am short.

::有时，我真的很高。其他时候，我很矮。这要看情况。如果你早上在外面，我是高的。在下午晚些时候，我也很高。中午左右，我很矮。

I go where you go.

You move and I move.

I may appear on the ground.

I may also appear on a wall.

Do you know what I am?

That’s right, I am your shadow.

::你去哪儿我就去哪儿。你动我也动。我可能会出现在地上。我也可能出现在墙上。你知道我是什么吗？没错，我是你的影子。

Shadows can appear when light is blocked.

Only certain things can have shadows.

A glass window does not have a shadow.

Do you know why?

::当光线被遮挡时，阴影就会出现。只有某些东西才会有影子。玻璃窗没有影子。你知道为什么吗？

Light is able to pass through some material.

Light can pass through glass.

Shadows appear when light cannot pass through an object.

Shadows are areas where light is blocked.

::光能够穿过某些物质。光可以穿过玻璃。当光不能穿过物体时，就会出现阴影。阴影是光线被遮挡的区域。

Light travels in a straight line.

If it didn’t, it would wrap around you.

You would not have a shadow.

Because it does travel in a straight line, light is blocked by

your shape.

You move and your shadow moves.

How can you make your shadow move?

::光沿直线传播。如果没有，它就会缠着你。你就不会有影子了。因为光线是沿直线传播的，所以光线会被你的形状挡住。你移动，你的影子也移动。你怎样才能让你的影子移动？

Where your shadow appears depends on where the light comes from. 

If light comes from your left, your shadow will be on your right.

If the light is coming from behind you, your shadow will be in

front of you.

That’s why your shadow changes during the day.

The Sun is a light source.

::你的影子出现在哪里取决于光来自哪里。如果光从你的左边来，你的影子就会在你的右边。如果光来自你的背后，你的影子就会在你的前面。这就是为什么你的影子在白天会发生变化。太阳是一个光源。

If the Sun is going down, your shadow will be long.

If the Sun is coming up, your shadow will be long.

If the Sun is directly over your head, where is your shadow?

That’s right!

Your shadow will be below you.

Your shadow is always opposite the light source.

::如果太阳下山了，你的影子会很长。如果太阳出来了，你的影子会很长。如果太阳正对着你的头顶，你的影子在哪里？这是正确的!你的影子会在你下面。你的影子总是对着光源。

Where else can you see shadows?

How do they move during the day?

Look around and see how many objects have shadows.

Do you see me?

I am your shadow?

::你还能在哪里看到阴影？它们白天是怎么活动的？看看周围有多少物体有阴影。你看到我了吗？我是你的影子？