单选题 《复合题被拆开情况》 When men grow older, their hair often begins to fall out. When hair begins to fall out【C1】________ old age, it is impossible to make it【C2】________again. I know a man who found【C3】________his hair was beginning to fall out on his fortieth birthday. He bought some ointment(药膏) and used it on his head.【C4】________ointment was very expensive. It【C5】________$50 for a small can! He used the ointment on his head【C6】________a day. Every day he【C7】________into his mirror’(镜子) to see【C8】________his hair was growing again, but the ointment was【C9】________good. Every day more and more hair fell out and【C10】________there was no hair left on his head.《问题》：【C5】