题目

One day．a poor boy who was trying to pay his school expenses by selling goods from door to door found that he had only one quarter left．He was hungry so he decided to    36    for a meal at the next house． 37    ,he lost his nerve when a lovely young woman opened the door．Instead of a meal he asked for a drink of water．She thought he looked    38    so she brought him a large glass of milk．He drank it 39__, and then asked, How much do I owe you? You don't owe me anything, she     40   . Mother has taught me never to accept pay for a  41__． He said,－You _______ be happy with the strong public support you’ve received.－Yes,you’re right.I’m really excited.A．mayB．can C．mustD．need