Take a close look at these mysterious track in the sky
Think of what happens when you are outside on a very cold day. As you breathe in, the air becomes warm inside your body, and when you breathe out, you see a small cloud form. This is the key principlebehind condensationtrails, or contrails.
Contrails are left behind by airplanes passing in the sky. However, you may wonder why you see contrails on some days and not on others. As with your breath on a cold day, contrails only appear when planes are flying through cold, humidair. The plane’s enginescreate and release hot water vapor. When this water vapor hits the cold air at high altitudes, it becomes drops of water. If the temperature is low enough, it may freeze to form tiny ice crystals. These ice crystals are what make contrails visible.
The length and visibilityof a contrail depend on conditions in the atmosphere. The colder and damperthe air is when a plane flies through, the longer and clearer a contrail will be. On relativelydry days, a contrail will disappearas soon asthe plane flies away.
單字片語整理
Words in Use
●
mysterious
[mɪsˋtɪrɪəs]
a. 神祕的
=
mythical
David Copperfield’s magic was so mysterious that everyone was amazed.
大衛•考柏菲的魔術很神祕，讓每個人都很著迷。
高中 Level 4
●
principle
[ˋprɪnsəp!]
n. 原則，原理；道德原則，行為準則
I agree with you in principle; it is your method that I disagree with. 原則上我同意你；我不同意的是你的方法。
You can trust Ned. He’s a man of principle.
你可以信任奈德，他是個有道德準則的人。
多益金色
英檢初級
高中 Level 2
●
humid
[ˋhjumɪd]
a. 溼氣重的
=
damp
=
moist
In the summer, the weather is generally hot and humid.
夏季時，天氣通常又熱又潮溼。
高中 Level 3
●
engine
[ˋɛndʒən]
n. 引擎；火車頭
My car wouldn’t move because there was something wrong with the engine.
我的車動不了，因為引擎有毛病了。
高中 Level 2
●
atmosphere
[ˋætməs͵fɪr]
n. 大氣；空氣；氛圍
=
feeling
=
mood
The satellite is fixed at a point just outside the Earth’s atmosphere.
那枚衛星被安置在地球大氣層外的某個定點上。
Mildew easily forms in my room because of the damp atmosphere.
因為空氣很潮溼，我的房間很容易長黴。
I like the warm and pleasant atmosphere in that coffee shop.
我喜歡那家咖啡廳溫暖又愉快的氣氛。
多益綠色
英檢中級
高中 Level 4
●
relatively
[ˋrɛlətɪvlɪ]
adv. 相對地，蠻
It was quite cold yesterday, but it is relatively hot today.
昨天很冷，不過今天相對較熱。
多益藍色
英檢中級
高中 Level 1
●
contrail
[ˋkɑn͵trel]
n. (飛機航行中形成的)凝結尾
●
condensation
[͵kɑndɛnˋseʃən]
n. 凝結
●
vapor
[ˋvepɚ]
n. . 蒸氣
The doctor used water vaporto treat my sore throat.
醫生用水蒸氣來治療我的喉嚨痛。
英檢中級
高中 Level 6
●
altitude
[ˋæltə͵tjud]
a. . （海拔）高度
=
attitude
The airplane is now cruising at an altitude of 30,000
feet.
這架飛機正在 3 萬英尺高空飛行。
英檢中級
高中 Level 6
●
crystal
[ˋkrɪst!]
n. 水晶 & a. 水晶（製）的；清澈的
Even though her ring only has a crystal on top, Julie tells people it’s a diamond.
儘管茱麗的戒指上只有一顆水晶，她卻告訴別人那是鑽石。
Peter has a fine collection of crystal glasses.
彼得珍藏了許多高級水晶酒杯。
高中 Level 5
●
visibility
[͵vɪzəˋbɪlətɪ]
n. 能見度
●
damp
[dæmp]
a. 潮溼的
n. 溼氣（不可數）
vt. 使潮溼
=
moist
=
humid
The lawn was damp with dew.
草地被露水弄得溼溼的。
The clothes hadn’t dried properly and still smelled of damp.
這些衣服沒有全乾，仍聞得出溼氣的味道。
The light rain shower had barely damped the ground.
綿綿細雨幾乎沒怎麼弄溼地面。
The light rain shower had barely dampened the ground.
綿綿細雨幾乎沒怎麼弄溼地面。
多益藍色
英檢中級
高中 Level 4
Practical Phrases
●
leave... behind / leave behind...
拋下⋯⋯；留下⋯⋯
Sam could not leave behind the fun of city life, so he chose to work in the big city.
山姆無法拋下都市生活的樂趣，所以選擇在大城市工作。
●
as soon as...
一……就……
The boy cried as soon as he saw the stranger.
小男孩一看到那個陌生人就哭了。
保留句首的疑問詞，再將 do、does 或 did 去掉，
其後的原形動詞則按主詞人稱及時態作變化。
例: Where does Tim live? → where Tim lives
問句主詞為 who、what、which
變成名詞子句時，句構不變。
例: What happened? → what happened
★ 名詞子句的功能：
1. 作主詞： 例: What Sam said was not nice.
山姆說的話很不好聽。 2. 作及物動詞或介詞的受詞： 例: I donʼt remember where my keys are.
我不記得我的鑰匙在哪裡。 3. 置於 be 動詞後作主詞補語： 例: The important thing is how you handle the problem.
重要的是你如何處理這個問題。
請將下列字詞組合成一正確通順的句子 ❶ Wet clothes donʼt dry easily _______________________________.
such / weather / in / humid ❷ Charlie is always ________________________________.
in / relatively / a group / quiet ❸ The party began __________________________
答案: 1. Wet clothes don’t dry easily in such humid weather.
2. Charlie is always relatively quiet in a group.
3. The party began as soon as everyone arrived.
