题目

Every year there is a Spring Festival in China. Usually it is in January or February. It is the most important festival in China. So before it comes, everyone has to prepare things. They buy pork， beef, chicken, fruits and many other things. And they often make a special kind of food—“dumplings”. It means “come together”. On the day before the festival, parents buy new clothes for their children. Children also buy presents for their parents. On the Spring Festival Eve (除夕)，all the family members come back to their hometown. This is a happy moment. Some sing and dance,有一列数：2，22，222，2222，…，把它们的前27个数相加，那么所求的和的十位数字是（　　）A．3B．5C．7D．9