C．A meaningful summer vacation

　　D．Y－Corps: two service trips

　　答案：A　标题判断题。根据首段以及全文内容可以得知，本文主要叙述了作者去美国北部印第安纳波利斯的一次令人难忘的义务服务旅行的情况，故选A。

　　B

　　In our life journey, we each have important roles to play. Some are conductors and some are soloists (独唱者). And the rest are heroes in the supporting cast (配角演员) and are necessary to complete the different tasks in life. The "stars" would be greatly darkened if the individual heroes don't support their performances. The magical accents of the percussion (打击乐器) section might sound terrible and out of place, unless you could also hear the music they accompany. Even one member of an orchestra doing less than their best could stop the harmony of the musical piece.

　　So, even though you may not receive the attention of the other performers, your contribution is invaluable and an integral (不可缺少的) part of the success of the whole in the life you lead.

　　When you do your job well, you put your own unique energy into the task. Each of us has a different personality and a different talent, just suited for the different roles we support. We can look around us at any moment and identify with the people we work with. Doing your job well displays your ability and gratitude, while learning the lessons can move us towards our goals.

　　When you are fully present in the job you do, you bring the fullness of your mind, body, and spirit to the moment. Your contribution is strengthened by the infusion (灌输) of your talents and abilities, and they can attract the right people and circumstances to your experience. You are playing your role to your very best. You are giving your best to the world and making it a better place for all of us to live in. Remember, each of us is expected the best.

篇章导读：本文是一篇议论文。每个人都有着各自不同的社会