用光学显微镜观察有丝分裂，若从细胞周期考虑，根据下表中提供的信息，选择合适的实验材料（）
A.物种甲
B.物种乙
C.物种丙
D.物种丁
参考答案：D
_____ is reported in the newspapers, talks between the two countries are making progress. [ ]
A. It
B. As
C. That
D. What
政策执行出现偏差的原因有哪些？
