题目

People say teenagers are no good. They make too much noise in shopping malls; they drive recklessly（不顾一切地） up and down America’s main streets; they carry chips on their shoulders as big as the Sears Tower. And at least some of the time those things are true. But we shouldn’t forget that there are hard moments in the life of a teenager too.I watched such a moment not long ago at a woman’s funeral. I didn’t expect the event to affect me. Through much of the ceremony, in fact, I remained unmoved.The teenage grandson stepped forward. With his very first deep breath, every hea血友病患者一旦有伤口便会流血不止的原因是血液中缺少（ ）A.红细胞 B.白细胞C.血小板 D.血红蛋白