英语听力文摘 English Digest 74、干旱的成因

　　For those of us lucky enough to always have enough food and water, it may be hard to imagine living through a drought. A drought occurs for a variety of reasons, usually including a lack of rainfall and warm temperatures.Soil moisture severely¹ dwindles². Why and how do these meteorological events occur?
As air swirls³ around the earth, it rises and sinks over different areas of the globe. When air rises it cools and loses moisture. When air sinks, it grows warmer and absorbs moisture, drying out the land. Sinking air helps to form deserts, such as the Sahara Desert in Africa.
Warm, sinking air can hamper⁴ cloud formation, which results in less rain and lower overall humidity. 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. The Dust Bowl that affected⁶ the prairie regions of the United States was one infamous⁷ drought. An equally severe drought occurred in the United States in the summer of 1988. Rainfall over the mid-west, Northern Plains, and the Rockies was fifty to eighty-five percent below normal.
Sometimes over-farming and soil erosion contribute to drought, but there are also natural disasters that can occur even when soil is carefully preserved. When a drought hits, there’s little that can be done to end it. Water and soil conservation can help, but until the rains come again there’s not much science can do.
meteorological:气象的
replenish:补充
ensue:因而产生
prairie:（北美）大草原
infamous:臭名昭著的
soil erosion:水土流失
conservation:保护，防止流失

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。