阅读短文，下列问题

A

    It's two weeks before Christmas in England and Mrs. Smith is very busy. She buys a lot of Christmas cards to send to her friends and to her husband's friends. She puts them on the table in the room. Then, when her husband comes home from work, she says to him, “These are the Christmas cards for your friends. Could you please write the cards and I cook supper?”

    Mr. Smith doesn't say anything and walks into his study. After a while, he comes with a box full of Christmas cards. He puts them on the table and says, “They are from last year. I forgot(忘记) to send them.”

在下面—段文字横线处补写恰当的语句，使整段文字语意完整连贯，内容贴切，逻辑严密。每处不超过15个字。

    谚语有云：“予人玫瑰，手有余香。”然而，①____，这样做是因为我们还没有认识到，给予是世界上最强大的力量，它对健康的好处超过你的想象。给予不仅能让人获得快乐、幸福的正面情绪，而且还能保护心脏，提高免疫力，降低抑郁和自杀风险，延长寿命等，总之，②____。其实，只要愿意，③____，你可以做慈善，帮助困难之人，你可以常怀感恩之心，谅解和尊重别人，你还可以绽放一个动人的微笑，说出一句由衷的赞美。

下图是小强同学在自主学习时整理的提纲，据此判断，他学习的内容是（    ）