题目

第二节：读写任务（共1小题，满分 25分） 阅读下面的一封信，然后按照要求写一篇150词左右的英语短文。 Recently I took part in an English speech contest and successfully went into the final. That day, I thought I had done a good job. At that moment I even had a strong feeling of being the champion. But my dream was soon shattered when my final score was announced. I stood in the hall, feeling empty-minded and puzzled. My memory went back to when I was in junior middle school. I took part in a similar speech contest. I was too proud of myself. I was not wel山羊的白毛和黑毛是一对相对性状，如图为山羊的毛色遗传图解。据图回答：（1）一对白毛山羊的后代中出现了黑毛山羊，在生物学上，这种现象叫做 。（2）根据遗传图解可以判断，白毛为 （填“显性”或“隐性”）性状。（3）山羊体细胞内染色体数目为30对，则其卵细胞中的染色体数目为 条。（4）如果显性基因用D表示，隐性基因用d表示，则子代中黑毛山羊的基因组成是 。（5）如果这对白毛山羊再生一只小羊，这只小羊是白毛的可能性是 。