任务型阅读mary and her mother are on the way to a store .they wan

任务型阅读
mary and her mother are on the way to a store .they wany to duy some food .they meet a doy .he doeso't have much money.he looks at penple and wants them to help him "he is healthy .he can buy food and clothes by himself "says a girl .she doesn't help the boy.mary's mother goes to the boy and gives him money"i only know he needs help."says mary 's mother "and he needs some food ,too"says mary .then she buys a sandwich for the boy.we need to help others .but we needn't find why they need help
1.mary buys ______for the boy