阅读理解。 A new study in West Africa shows

问题：

阅读理解。

     A new study in West Africa shows how farm irrigation systems powered by the sun can produce

more food and money for villagers. The study in Benin found that solar-powered pumps are effective in

supplying water, especially during the long dry season.

     Sub-Saharan Africa is the part of the world with the least food security. The United Nations Food and

Agriculture Organization estimates that more than one billion of the world's people faced hunger last year.

Around two hundred sixty-five million of them live south of the Sahara Desert. Lack of rainfall is one of

their main causes of food shortages.

     Jennifer Burney from Stanford University in California led the study. The research team helped build

three solar-powered irrigation systems in northern Benin.The solar-powered irrigation systems produced

an average of nearly two metric tons of vegetables per month.They sold the surplus (过剩的) produce at

local markets. The earnings greatly increased their ability to buy food during the dry season which can last

six to nine months. People in the two villages with the systems were able to eat three to five more serving

of vegetables per day. But making the surplus available at markets also had a wider effect.The study

compared the villages with two others where women farmed with traditional methods like carrying water

in buckets. The amount of vegetables eaten in those villages also increased, though not as much.

     The researchers note that only four percent of the cropland in sub-Saharan Africa is irrigated. Using

solar power to pump water has higher costs at first. But the study says it can be more economical in the

long term than using fuels like gasoline, diesel or kerosene. And solar power is environmentally friendly.

1. People living in sub-Saharan Africa are short of food mainly because ______.

A. it seldom rains there throughout the year

B. there is little farmland in the area

C.people there lack experience in farming

D.people know nothing about irrigation techniques

2. Which of the following is an advantage of Jennifer's irrigation systems?

A. They are not affected by the weather.

B. They cost much less than traditional irrigation systems.

C. They have no bad effects on the environment.

D. They use less fuel than traditional irrigation systems.

3. We can learn from the last paragraph that ______.

A. people in South Africa will soon be provided with enough food

B. the demand for fuels like gasoline will greatly decrease in Africa

C. people in sub-Saharan Africa don't take agriculture seriously

D. it's worthwhile to use the new irrigation systems on the whole

4. People in the two villages owe all the following to Jennifer's irrigation systems EXCEPT that ______.

A. they could buy more food during the dry season

B. they could eat more vegetables than usual every day

C. they could supply local markets with vegetables

D. they could provide people in other villages with food