第一节 完形填空（共20小题；每题1.5分，满分30分）

　　阅读下面短文，从短文后各题所给的A、 B 、C 和D四个选项中，选出可以填入空白处的最佳选项。

　　　　　　　　　　A Commitment to Life

　　The snow was falling and the roads had become dangerous. The schools were dismissed early, but much to my surprise, my __1__ wasn't canceled. So I went, feeling especially heroic. As far as I could see, I was risking my life to keep my __2__. Snow or no snow, I would be on time for my scheduled donation at the local __3__ center.

　　When I got there, I discovered I wasn't __4__. Four more "hero-types" were already lying back in donor chairs with lines __5__ to their veins(静脉), and machines quietly pumping away to __6__ their lifesaving gifts.

　　Seeing my fellow donors honoring their own commitments, I realized why I was there. I lay back in my donor chair, ready to make a __7__ to the life of someone I would never __8__.

　　To be honest, I'd never really thought about why I donate. I just did it. __9__ a few months ago, during one of my __10__ donations I learned that my blood was specifically for a cancer patient and for a newborn baby-both patients needed what I would give in order to live. I've viewed my visits to the blood center __11__ ever since.

　　My wife Karen is a __12__, too. And more importantly, she has been on the bone marrow (骨髓) list for fifteen years, ever since she __13__ to provide bone marrow to a kindergartner with leukemia(白血病). That little girl died before Karen's bone marrow could help her, but Karen was called again recently. Her test results were still on file, and it turned out she was a potential __14__ for someone else. The caller asked Karen if she would still be willing to become a bone marrow donor. "Yes," she said and then immediately began answering questions on the pages of paperwork for further testing. It was a race __15__ time.

I wish I could say that this __16__ was won. It wasn't. The caller later thanked