特发性血小板减少性紫癜最主要的发病机制是:()
A.骨髓巨核细胞成熟障碍
B.脾脏吞噬血小板增多
C.血小板功能异常
D.血清中有抗血小板抗体
E.骨髓造血功能低下
参考答案:D
Good harvest this year has made it possible for us to supply walnuts ______ last year's prices.
A. at B. in C. against D. on
严格执行国家对()未成年工的保护规定,禁止安排未成年工从事过重、有毒、有害等劳动或危险作业。