D．To deal with the hunger problem.

　　解析：选D　细节理解题。根据第二段中的"helping people grow their own food is a better way to fight hunger. That is the purpose of an agricultural research organization called HarvestPlus"可知，HarvestPlus这个组织的目的是要解决饥饿问题。

　　2．What's special about orange sweet potatoes?

　　A．They have more vitamin A.

　　B．They sell better in villages.

　　C．They taste much sweeter.

　　D．They are easier to plant.

　　解析：选A　细节理解题。根据第四段中的"white and yellow sweet potatoes, which have very little vitamin A"和"one small, orange sweet potato has a full day's supply of vitamin A"可知，橙色的红薯含有更多的维生素A。

　　3．What surprised the researchers?

　　A．Diarrhea was extremely common in Mozambique villages.

　　B．Orange sweet potatoes strongly influenced children's health.

　　C．Most children in Mozambique weren't getting enough vitamin A.

　　D．There was a big difference in the health of children of different ages.

　　解析：选B　推理判断题。根据倒数第二段中的"the potatoes had a surprising influence on the health of children"以及接下来的研究结果可知，橙色红薯对儿童的健康有着巨大作用，这让研究者感到非常诧异。

　　4．In Anne Herforth's opinion, ________.

　　A．connecting food with health is useful

　　B．people should try their best to produce natural food

　　C．agriculture and health problems always go hand in hand　

　　D．it's more important to produce healthy food than delicious food

　　解析：选A　推理判断题。根据最后一段中的"Anne Herforth ... says the findings do a good job making the connection between food production and health."以及他接下来说的话可知，他认为将食物和健康联系在一起是有用的。

　　B

On December 14, 1911, Norwegian explorer Roald Amundsen and his four­man team became the first people to reach the South Pole, where they raised the Norwegian flag in victory. On Wednesday, exactly 100 years later, Norway's prime minister gathered with scientists and polar adventurers at the bottom of the world to remember the famous explorer's achievements. "We are here to celebrate one of the greatest feats (功绩) in human history，" Prime Minister Jens Stoltenberg said.