英語聽力文摘 “勒不死”的蒼蠅

你絕對勒不死蒼蠅

Don:These dark flies are driving me badly! I wish I could strangle each of every one of them!

Yaël:I’m sorry to say, but that’s impossible.

D: I realize that. I don’t mean that I have to strangle all of them. Really, I did happy if I could strangle even just one or two of them.

Y: Impossible!

D: I’m sure. I can just manage to just strangle one if I had some dental flosses or something.

Y: I’m sure you couldn’t because insects breathe quite differently from us. They don’t have a central area like our lungs where they gather oxygen; nor a transport system like our heart, and the blood used to deliver oxygen to all of our cells.

Nope. Flies, like all insects, breathe through many tiny openings called spiracles. These openings are part of tubes called trachea. Each tube leads to a fluid-filled tracheole, where the oxygendissolves and then diffuses across the wall of the tracheole and into several of the insect’s cells. So there is no central breathing area to block off so that you might strangle a fly.

However, if you wanted to drown a fly, that’s another story. The spiracles of most insects can close to keep things like dust out. Therefore, they can hold their breath, so to speak. But if an insect is trapped in water for too long, it will run out of oxygen and eventually drown.

D: Now, I just have to figure out how to lure them all into some water.

Don: 這些飛來飛去的黑蒼蠅快把我逼瘋了!我真想把他們?nèi)坷账?

Yaël: 很遺憾，你辦不到!

D:我知道，要全部都勒死不容易，不過，哪怕勒死那么一兩只也好啊!

Y:你還是辦不到!

D:我保證如果有類似牙線的東西，我肯定能勒死一只蒼蠅。

Y:我打賭你做不到。因?yàn)槔ハx呼吸可不像我們?nèi)祟惖?。昆蟲既沒有肺似的中心區(qū)域，可以容納空氣;也沒有像心臟似的運(yùn)輸系統(tǒng)，可以通過血液循環(huán)，給身體所有細(xì)胞供氧。

蒼蠅，和所有昆蟲一樣，通過無數(shù)微小的氣門來進(jìn)行呼吸。氣門是氣管的部分。氣管又分支成許多微氣管，微氣管里充滿液體，吸入的氧氣溶解于其中，穿透氣管管壁擴(kuò)散到昆蟲的無數(shù)細(xì)胞中。所以， 你沒方法讓蒼蠅窒息。

但是，如果你想讓蒼蠅淹死，又是另外回事了。大多數(shù)昆蟲緊密氣門，防止灰塵進(jìn)入。這樣，它們不得不屏住呼吸，但是如果在水里太長時間，它們會因?yàn)槿毖醵缢馈?/p>

D:那么，現(xiàn)在我只要想法子讓蒼蠅掉進(jìn)水里就可以啦!

diffuse:擴(kuò)散，彌漫

cell: 細(xì)胞