具有催化活性的RNA 分子被称为（）
A. 核酸酶
B. 核糖核酸酶
C. 核酶
D. RNA 酶
E. 非编码RNA 酶
The author write this passage mainly to______.
A. bring up some facts about AIDS preventing and curing in the world.
B. urge Chinese government to do something about AIDS.
C. compare two countries in the AIDS-related work.
D. say something about the development in the AIDS preventing method.
女性，42 岁，乏力半年，登楼困难2 周。半年前发现高血压，药物治疗无效。查体：BP 140/92mmHg，心率90 次份。血糖6.2mmol/L，血钾2.8mmol/L，B 超示：左肾上腺区域有1.5cm 大小圆形低回声区，可能的诊断是（）
A. 嗜铬细胞瘤
B. 肾上腺髓质增生
C. 原发性醛固酮增多症
D. 肾上腺皮质肿瘤
E. Cushing 病
It can be inferred from the passage that China fall behind South Africa because ______.
A. there are not enough medical experts in AIDS.
B. the government's attitude toward AIDS problem is still to be changed.
C. of the lack of experience.
D. china have not enough money.
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