美国英语听力80篇1 Lesson20

[00:06.48]Lack of Vitamin¹ A is the leading cause of blindness among children in deveoping countries.
[00:14.55]These children do not get enough Vitamin A in the food they eat.
[00:21.11]In Africa,more than 3,000,000 children suffer from blindness or sickness caused by lack of Bitamin A.
[00:30.17]Scientists say sweet potatoes are rich in beta carotene--the natural orange-colored substance² that the human body needs to produce Vitamin A.
[00:43.23]One recent study found that orange-colored sweet potatoes are an excellent food for families in southern and eastern Africa.
[00:53.89]Scientists from Kenya,Uganda and the International Potato Center in Peru³ supervised⁴ the ten-year study.
[01:03.87]The scientists found that several kinds of sweet potatoes produce excellent harvests in some areas where Bitamin A deficiency⁵ is widespread⁶.
[01:16.33]They said sweet potatoes provided⁷ large amounts of Vitamin A at a very low cost.
[01:24.09]People in Africa liked the orange-colored sweet potatoes used in the study.
[01:30.72]Some people had thought Africans would not acceppt such potatoes because they are sweeter than locally-grown sweet potatoes.
[01:40.62]The traditional African sweet potato is white and contains little or no beta-carotene.
[01:48.98]However, research studies and taste tests showed the new sweet potatoes are able to compete with the local crops.
[01:58.26]Wanda Collins is a research official at the International Potato Center.
[02:04.94]She says the study found that mothers in Africa accepted the orange-colored sweet potatoes.
[02:13.15]Women who knew the value of these potatoes continued to buy them when food shortages⁸ caused price increases.
[02:22.89]Ms.Collins says the next step is to develop this important crop in other areas of Africa.
[02:32.42]The International Potato Center reports that many women and girls in southern and eastern Africa grow sweet potatoes.
[02:42.48]The crops are grown on small pieces of land used to produce family food supplies.
[02:48.96]African farmers produce almost 7;000,000 tons of sweet potatoes each year.
[02:56.51]However, the production rate is only about five tons per hectare⁹.
[03:02.36]In all developing countries, the average production rate is fifteen tons per hectare

1 vitamin   

n.维他命，维生素

参考例句：

• Oranges are rich in vitamin C.橙子富含维生素C。
• Vitamin pills make up what you lack in your diet.维生素丸可补充你食物中所缺乏的营养。

2 substance   

n.物质，实质，主旨

参考例句：

• There isn't anything of real substance in her book.她的书中没有任何真正实质性的内容。
• How long will the substance take to salt out?这种物质需要多长时间来盐析？

3 Peru   

n.秘鲁(南美洲国家)

参考例句：

• Lima is the capital of peru.利马是秘鲁的首都。
• China and peru are friendly countries.中国和秘鲁是友好国家。

4 supervised   

v.监督，管理( supervise的过去式和过去分词 )

参考例句：

• The architect supervised the building of the house. 建筑工程师监督房子的施工。 来自《简明英汉词典》
• He supervised and trained more than 400 volunteers. 他指导和培训了400多名志愿者。 来自辞典例句

5 deficiency   

n.缺乏，不足，缺点，缺陷

参考例句：

• During the war children suffered from a deficiency of food.战争期间孩子们遭受缺乏食物之苦。
• Fortunately,color deficiency is not a serious medical problem.幸运的是，色盲并不是一种严重的医学问题。

6 widespread   

adj.广布的，普及的，流传宽广的

参考例句：

• Plastic is in widespread use.塑料已被广泛地使用。
• English is a widespread language.英语是一种很普及的语言。

7 provided   

conj.假如，若是；adj.预备好的，由...供给的

参考例句：

• Provided it's fine we will have a pleasant holiday.如果天气良好，我们的假日将过得非常愉快。
• I will come provided that it's not raining tomorrow.如果明天不下雨，我就来。

8 shortages   

n.不足( shortage的名词复数 )；缺少；缺少量；不足额

参考例句：

• Food shortages often occur in time of war. 在战争期间常常发生粮食短缺的情形。 来自《现代汉英综合大词典》
• At the same time, worldwide food and fuel shortages eased. 同时，世界性粮食和石油短缺的现象终止了。 来自英汉非文学 - 政府文件

9 hectare   

n.公顷

参考例句：

• A hectare is equal to 15 mu.1公顷合15市亩。
• The lands were to be sold at $2.50 per hectare.土地的售价为每公顷2.50美元。