问题
单项选择题
使用有机溶剂沉淀法得到的核酸,往往含有少量共沉淀的盐,可用多少浓度的乙醇洗涤去除()
A.20%
B.35%
C.45%
D.70%
E.95%
答案
参考答案:D
使用有机溶剂沉淀法得到的核酸,往往含有少量共沉淀的盐,可用多少浓度的乙醇洗涤去除()
A.20%
B.35%
C.45%
D.70%
E.95%
参考答案:D
情景交际(有两项为多余项) 。 | |
A: Roger, What's the matter? You look pale. Are you sick? B: 1 A: Sit down, please. 2 B: No, thanks, Felix. I'll be fine soon. A: 3 B: Not quite, but almost. A car almost knocked me down when I crossed the road just now. Luckily, I jumped back in time. A: 4 The police should take away the license from the driver like that. B: I think so. I can't forget this for a long time. A: I'm sure you won't forget it. 5 B: OK. I will.
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