题目内容：
听材料，回答下列问题：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 _____26_____ in supplying water, especially during the long dry season.
Sub-Saharan Africa is the part of the world with the least food _____27_____. The United Nations Food and Agriculture Organization28that more than one billion of the world's people faced hunger last year.
Around 265 million of them live south of the Sahara Desert. _____29_____ 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 _____30_____ irrigation systems in northern Benin. Between thirty and thirty-five women used each system to pump water from the ground or a stream. Each woman _____31_____ farming her own 120 square meters of land. They also farmed other land collectively.
The solar-powered _____32_____ systems produced an average of nearly two metric tons of vegetables per month. During the first year, the women kept a monthly average of almost nine kilograms of vegetables for home use. They sold the _____33_____ produce at local markets. The earnings greatly increased their ability to buy food during the dry season which can last six to nine months.
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 _____34_____. But the study says it can be more economical in the long term than using fossil fuels like gasoline. And solar power is _____35_____ friendly.
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