英语听力文摘 English Digest 79、飞机造成的耳朵不适

　　When traveling by plane what makes our ears pop, and what is it exactly that pops? Most of us are familiar with this phenomenon of travel: it usually happens on takeoffs and landings.
Our ears pop because of the change in air pressure as the plane ascends¹ or descends². At higher altitudes air pressure is lower, even though the plane is pressurized. Our ears are sealed off inside our heads, so as the plane ascends or descends the pressure outside and inside our ears is different. This difference in pressure can distort our ear drums and can be painful.
What needs to be done here is to equalize the pressure between our ears and the airplane cabin. Nature has provided the means for this with a tube that runs from the middle ear to the nasopharynx–the open area behind our noses. It’s called the Eustachian tube. Normally the Eustachian tube is closed;so in order to equalize the pressure we need to open it. Seasoned travelers know that you can avoid the discomfort³ by swallowing or chewing gum when you feel the pressure change. The mechanical action when we chew gum or swallow opens the Eustachian tube, and allows the pressure to be equalized. The opening of the Eustachian tube is associated with the “pop” we hear.
Incidentally, babies often cry on takeoff and landing because they don’t know to chew or swallow. Having them suck on something can open their Eustachian tubes and alleviate⁴ the pain– on their ears and the other passengers.
pop:发出爆炸声
ascend:上升
descend:下降
pressure:压力，气压
airplane cabin:机舱
chew:咀嚼
gum:口香糖

1 ascends   

v.上升，攀登( ascend的第三人称单数 )

参考例句：

• The azygos vein ascends in the right paravertebral gutter. 奇静脉在右侧脊柱旁沟内上升。 来自辞典例句
• The mortality curve ascends gradually to a plateau at age 65. 死亡曲线逐渐上升，到65岁时成平稳状态。 来自辞典例句

2 descends   

v.下来( descend的第三人称单数 )；下去；下降；下斜

参考例句：

• This festival descends from a religious rite. 这个节日起源于宗教仪式。 来自《简明英汉词典》
• The path descends steeply to the village. 小路陡直而下直到村子。 来自《简明英汉词典》

3 discomfort   

n.不舒服，不安，难过，困难，不方便

参考例句：

• One has to bear a little discomfort while travelling.旅行中总要忍受一点不便。
• She turned red with discomfort when the teacher spoke.老师讲话时她不好意思地红着脸。

4 alleviate   

v.减轻，缓和，缓解(痛苦等)

参考例句：

• The doctor gave her an injection to alleviate the pain.医生给她注射以减轻疼痛。
• Nothing could alleviate his distress.什么都不能减轻他的痛苦。