题目

—Pity you missed the lecture on nuclear pollution. —I_______it, but I was busy preparing for a job interview. A. attended B. had attendedC. would attend D. would have attended 答案：D4个精原细胞经过减数分裂，形成（　　）? A.4个二倍体的精细胞? B.8个单倍体的精细胞? C.16个单倍体的精细胞? D.4个单倍体的精细胞?