题目

（2011·重庆师大附中月考）While he was investigating ways to improve the telescope, Newton made ________ discovery which completely changed ________ man’s understanding of color. A. a; 不填                 B. a; the                   C. 不填; the               D. the; a 答案：A考查冠词的用法。第一空表示“一个发现”；第二空understanding of color已有限定词man’s，故不用冠词。某生物父本基因型为AABb，母本基因型为AaBb，其子代中不可能出现的基因型是(　　)A. aabb B. AABb C. AaBb D. AAbb