听力文摘：干旱

For those of us lucky enough to always have enough food andwater, it may be hard to imagine living through a drought.

对于我们这些足够幸运能够有充足的食物和充沛的水资源的人来说，干旱是无法想象的。

A drought occurs when for a variety of reasons, usually includinga lack of rainfall and warm temperatures.

引起干旱的原因有许多，通常情况下是由降雨量少和高温引起的。

Soil moisture severely¹ dwindles².

干旱会使土壤含水量严重减少。

Why and how do these meteorological event soccur?

那接下来我们就来谈谈为什么会发生这些气候事件，它们又是如何发生的。

As air swirls³ around the earth, it rises and sinks over different areas of the globe.

厚厚的大气层将地球包围着，并在地球的不同地区上下沉浮着。

When air rises itcools and loses moisture.

当空气上升时，水蒸气会被冷却，空气中的水分会越来越少。

When air sinks, it grows warmer and absorbs moisture, drying out theland.

当空气下沉时，气温会逐渐升高，同时，还会吸收土壤中的水分，这样一来空气的湿度会随之增大，而土地却会变得干燥。

Sinking air helps to form deserts, such as the Sahara Desert in Africa.

下沉的空气对沙漠的形成可谓是“功不可没”，举世闻名的非洲撒哈拉大沙漠便是如此形成的。

Warm, sinking air can hamper⁴ cloud formation, which results in less rain and lower overall humidity.

下沉的湿热气流会阻碍云的形成，如此一来，该地区会少雨且空气湿度低。

When these conditions occur in an area that normally receives enough rain to allow plants to grow and keep water sources replenished⁵, a drought can ensue.

当这些现象发生在雨水充足到足以浇灌植物且能保证有充足水源的地方的话，干旱可能会接二连三的降临。

The Dust Bowl that affected⁶ the prairie regions of the United States was one infamous⁷ drought.

早年波及美国草原地区的大沙尘暴便是一次“名震全世界”的干旱。

An equally severe drought occurred in the United States in the summer of 1988.

1988年夏天在美国又发生了一次可与之匹敌的大旱。

Rainfall over the mid-west,Northern Plains, and the Rockies was fifty to eighty-five percent below normal.

美国中西部，北部平原及落基山脉的降水量比正常降雨量少了50%至85%。

Sometimes over-farming and soil erosion contribute to drought, but there are also natural disasters that can occur even when soil is carefully preserved.

有时，过度开垦和水土流失也会导致干旱，但是也有这样的情况，即使是土壤被小心地保护起来了，这样的自然灾害同样会发生。

And when a drought hits, there'slittle that can be done to end it.

另外，如果发生了干旱，人类几乎可以说是束手无策，没有办法人为地将其结束。

Water and soil conservation can help, but until the rains comeagain there's not much science can do.

保持水土不流失会有一定的帮助，但是，在再次降雨之前我们的科学也没什么办法。

1 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

2 dwindles   

v.逐渐变少或变小( dwindle的第三人称单数 )

参考例句：

• Her husband grows rich in crime, her significance dwindles. 她的丈夫罪恶累累，她的形象也受到损害。 来自辞典例句
• The voice died away and ceased, as an insect's tiny trumpet dwindles swiftly into silence. 这声音逐渐消失，就象昆虫的小喇叭嘎然而止。 来自辞典例句

3 swirls   

n.旋转( swirl的名词复数 )；卷状物；漩涡；尘旋v.旋转，打旋( swirl的第三人称单数 )

参考例句：

• Swirls of smoke rose through the trees. 树林中升起盘旋的青烟。 来自辞典例句
• On reaching the southeast corner of Himalaya-Tibet, It'swirls cyclonically across the Yunnan Plateau. 在到达喜马拉雅--西藏高原东南角处，它作气旋性转向越过云南高原。 来自辞典例句

4 hamper   

vt.妨碍，束缚，限制；n.(有盖的)大篮子

参考例句：

• There are some apples in a picnic hamper.在野餐用的大篮子里有许多苹果。
• The emergence of such problems seriously hamper the development of enterprises.这些问题的出现严重阻碍了企业的发展。

5 replenished   

补充( replenish的过去式和过去分词 )； 重新装满

参考例句：

• She replenished her wardrobe. 她添置了衣服。
• She has replenished a leather [fur] coat recently. 她最近添置了一件皮袄。

6 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

7 infamous   

adj.声名狼藉的，臭名昭著的，邪恶的

参考例句：

• He was infamous for his anti-feminist attitudes.他因反对女性主义而声名狼藉。
• I was shocked by her infamous behaviour.她的无耻行径令我震惊。