题目

You are probably familiar with the saying：An apple a day keeps the doctor away. A recent research carried out by the Chinese University of Hong Kong may change the saying:An apple a day may keep aging away.The research chose fruit flies(果蝇), as they share many genes(基因)with humans. The fruit flies were either fed normally or had an apple extract(浓缩物) added to their diet.It turned out that those fruit flies that were given apple extract lived about 55 days—five days longer than the flies that were normally fed. The research group also found it easier for the flies to walk，cl2008北京奥运现在开幕 用竖式计算 (1)507＋395 (2)431＋229 (3)346＋254