阅读下面短文, 掌握大意, 然后从A、B、C、D四个选项中选出最佳选项。
Around the corner sat an old vagrant(流浪汉), Bill, begging for money every day. However, there was1a disappointment in his eyes. One day, Sarah came up and gave him $20, a large amount of money for Bill. He was so confused that he asked her2she gave him so much money.
Sarah replied with a3, "I believe what goes around, comes around." With these words, she left happily4knowing something might happen to her. After she left, Bill found a5in his cup. Immediately he realized it should be Sarah's.
He looked all around but couldn't find her anywhere. Just as he6, he happened to come across a pawn shop(当铺).And after a few7, he decided to go inside to see how much this ring is worth.
"Four thousand dollars?"" he was8,"I wouldn't have to sleep on the street for months, if..."To sell or not, he was lost in thought.9, he took back the ring and left away.
For next weeks, he10looking for Sarah, but ended up with no result. Tired and11, one day he knocked on the door of a bookstore. Unexpectedly, there sat Sarah, working as usual.
Sarah was surprised in tears, "But I don't understand. Why did you12the ring? It could bring you plenty of13and even change your life."
"It's the least I could do. "Bill explained, "It was a wise lady who teaches14what goes around, comes around."
Thankful and totally moved, Sarah shared this story on the web to help collect money for Bill Only within a few days, she15over $100,000. Then on a spring morning, in Bill's cup, there was a cheque (支票) with a note, saying "What goes around, comes around".