题目

 Twelve years ago, I arrived in Central Florida from Puerto Rico. I had heard of a job opportunity and decided to pursue it. But it never became a reality. I quickly learned that being alone without resources in an unfamiliar city was not a comfortable situation to be in.  Once my limited funds ran out I became homeless and spent a year and a half living on the streets of Orlando. Apart from feeling not being noticed and missing my family, I had to face another challenge—hunger.  For the first time in my life, I, as a foreign man, who had lived my life in the relative comfort of th在一个DNA分子中，胞嘧啶与鸟嘌呤之和占全部碱基数目的54％，其中一条链中腺嘌呤占该链碱基总数的28％，那么由它转录的RNA中腺嘌呤占碱基总数的A．18％　　　B．27％C．28％D．22％