Level 1 · Reading series
Lesson 25 · The Sound Behind the Door
Audio track 25
Listen first
Listen once before opening the English passage.
Open the English passage and hover for word help
Someone knocks on a door. You cannot see the person, but you can hear the sound. A knock makes the door vibrate. The vibration makes nearby air move, and the sound travels to your ears.
Sound can move through air, water, and solids. It needs matter to carry its energy, so it cannot travel through empty space. A thick door may reduce the sound, but some vibrations still pass through it.
Sentence practice
Play any sentence in Dicvo’s Jenny English voice. Before playing all, choose how many times each sentence plays. A practice pause about as long as the sentence follows each play, including before the next sentence. The complete reading remains above.
Choose a sentence to begin.
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Someone knocks on a door.
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You cannot see the person, but you can hear the sound.
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A knock makes the door vibrate.
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The vibration makes nearby air move, and the sound travels to your ears.
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Sound can move through air, water, and solids.
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It needs matter to carry its energy, so it cannot travel through empty space.
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A thick door may reduce the sound, but some vibrations still pass through it.
Check your understanding
After reading, state the main idea in one sentence and find a line that supports it.
Chinese translation
有人敲门。你看不到那个人，却听得到敲门声。敲击使门振动；门的振动又带动附近的空气，声音于是传到你的耳朵。
声音可以在空气、水和固体中传播。它需要物质来传递能量，无法穿过完全空无一物的空间。厚门可能使声音变小，但仍会有一些振动传过去。
Key words and expressions
Key terms have Chinese explanations. Hover over dotted words in the English passage for word help and pronunciation when available.
- knock
- 敲；敲门。
- hear
- 听见；与强调主动倾听的 listen 有区别。
- sound
- 声音。
- vibrate
- 振动。
- nearby
- 附近的；在附近。
- travel
- 传播；旅行。本文指声音传播。
- solid
- 固体；能够保持形状的物质。
- carry
- 携带；传递。
- energy
- 能量。
- empty space
- 空无一物的空间。
Background notes (Chinese)
声音是物质的振动依次传开的波。因此，在近乎真空的太空中，人的声音不能直接传播。电影里的宇宙飞船内有空气，所以人们可以交谈；飞船外的声音在现实中则无法像电影里那样传播。
资料来源：NASA 关于声音的教育资料。