引起继发性再生障碍性贫血最常见的病因是
A.药物及化学物质
B.物理因素
C.病毒感染
D.细菌感染
参考答案:A
根据实际情况回答下列问题.
1. What do you think of the sunglasses?
2. What does your mother think of the sunglasses?
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CPU能够直接访问的存储器是
A.软盘
B.硬盘
C.RAM
D.C-ROM